Are Twins Born on the Same Date?

[pivoxa15]

If two human siblings were born within 365 days of each other then they must be twins (i.e. born on the same date)?

Please explain.

 

[J77]

I would assume it not possible to get pregnant whilst pregnant...

However, more sprogs are easily conceived after the first one pops out, after 9 months.

Therefore, not twins.

Unless this is a riddle...

 

[jim mcnamara]

gestation period for humans is ~275-280 days - meaning a mother could have one baby born in January, conceive in February and give birth in November. Two non-twin kids form one mother in less than 365 days - per the wording of your question.

Now if you asked, "can a mother conceive twice and give birth normally twice (to two or more children) in one year" - the answer is no. They would have to be multiple births because 275 * 2 > 365

 

[Moonbear]

However, more sprogs are easily conceived after the first one pops out, after 9 months.

Not all that easily. It takes some time for ovulations to resume after one gives birth, though that time varies among individuals and whether or not one is breast feeding. But, still possible to have a baby born in January and another in December (especially if the second is a bit premature).

I'm also confused by the point of the question. Pivoxa, could you explain the reasining behind your question? Why would you think they're twins? Twins means they are conceived at the same time.

 

[pivoxa15]

The question may seem odd. Another way to ask it is:

Is it possible for two sibilings to be born within the same year but are not twins? So one baby at a time in mother's tummy but born within the same year although none born prematurely.

 

[Astronuc]

Is it possible for two sibilings to be born within the same year but are not twins? So one baby at a time in mother's womb but born within the same year although none born prematurely.

Yes - but it it not common. The first child could be born in Jan, and then the second conceived in late March or early April and then born in Dec. Obvoiusly, as Jim indicated, the first child would be conceived during the previous year. It is not possible to conceive, deliver and then conceive and deliver, in the same year, and not have premature children.

Usually however, a woman who breastfeeds delays subsequent ovulation, while breastfeeding.

I have one brother 14 months younger than me, so my parents go busy soon after I was born.

 

[DaveC426913]

Well this is my wife's field of expertise. If you could be more specific I might be able to give you details.

 

[pivoxa15]

Yes - but it it not common. The first child could be born in Jan, and then the second conceived in late March or early April and then born in Dec. Obvoiusly, as Jim indicated, the first child would be conceived during the previous year. It is not possible to conceive, deliver and then conceive and deliver, in the same year, and not have premature children.

Usually however, a woman who breastfeeds delays subsequent ovulation, while breastfeeding.

I have one brother 14 months younger than me, so my parents go busy soon after I was born.

What do you mean by conceived? The important thing is that the siblings are born (out of mother's stomach) in the same year but none born prematurely.

 

[Moonbear]

What do you mean by conceived? The important thing is that the siblings are born (out of mother's stomach) in the same year but none born prematurely.

Conception refers to fertilization...the time when intercourse actually occurred that the pregnancy was initiated. And, just for accuracy, since this is a science forum, embryos/fetuses develop within the uterus, not the stomach. If you wish to refer more generally to the area of the body rather than to internal organs, abdomen is an acceptable term.

So, yes, if you are referring to birth only, and not the entire pregnancy, then it is possible for two siblings to be born within the same year, although very uncommon for the reasons already discussed above.

 

[J77]

I must have some unusual friends then -- either that or they like the idea of maternity leave too much after the first has arrived

(My gf is also less than a year older than her younger sister.)

 

[pivoxa15]

I raised the question because I know two sibilings in the same year level which dosen't look alike enough to be twins.

So that is a chance that they were born at different times of the year.

 

[DaveC426913]

Ah.

Well, just because they're born at the same time doesn't mean they're identical twins. Certainly in this day and age of superovulation technology, it is quite possible that they are due to the simultaneous fertilization of two different ova (as opposed to the splitting of a single ovum after fertilization). That would make them no more twins than any other pair of siblings.

BTW, it is also possible (and has happened) that "twins" do not even share the same father.

 

[pivoxa15]

Conception refers to fertilization...the time when intercourse actually occurred that the pregnancy was initiated. And, just for accuracy, since this is a science forum, embryos/fetuses develop within the uterus, not the stomach. If you wish to refer more generally to the area of the body rather than to internal organs, abdomen is an acceptable term.

So, yes, if you are referring to birth only, and not the entire pregnancy, then it is possible for two siblings to be born within the same year, although very uncommon for the reasons already discussed above.

Offcourse, the stomach is for food processing.:)

 

[pivoxa15]

Ah.

Well, just because they're born at the same time doesn't mean they're identical twins. Certainly in this day and age of superovulation technology, it is quite possible that they are due to the simultaneous fertilization of two different ova (as opposed to the splitting of a single ovum after fertilization). That would make them no more twins than any other pair of siblings.

BTW, it is also possible (and has happened) that "twins" do not even share the same father.

Twins without the same father? That must be freaky as in low probability.

The sibilings I had in mind look alike enough to be sisters but not any kind of twin.

 

[brewnog]

Twins without the same father? That must be freaky as in low probability.

It only requires sperm from two separate men to be around two ova at a similar time. The low probability of it happening is largely because most women trying to get pregnant stick with one partner whilst doing it.

The sibilings I had in mind look alike enough to be sisters but not any kind of twin.

Someone correct me if I'm wrong, but non-identical twins don't typically look any more alike than any other siblings. An ex girlfriend of mine looked little like her (non-identical) twin sister, and my current girlfriend's twin is a boy...

 

[lah214]

Most fraternal (not sure if that's spelled right) twins do look similar. Mary-Kate and Ashly Olsen aren't identical twins, and they look it. (I didnt really want to use them as an example, but they are widely know).

But that can seriously happen?? Twins from different fathers?

 

[nrqed]

I raised the question because I know two sibilings in the same year level which dosen't look alike enough to be twins.

So that is a chance that they were born at different times of the year.

But they may simply be heterozygote twins! (i.e. two different embryos were fertilized at the same time). So they are born at the sam etime but don't have the same genetics. two heterozygote twins may even be of different sex!

 

[Moonbear]

The sibilings I had in mind look alike enough to be sisters but not any kind of twin.

Someone correct me if I'm wrong, but non-identical twins don't typically look any more alike than any other siblings. An ex girlfriend of mine looked little like her (non-identical) twin sister, and my current girlfriend's twin is a boy...

Precisely. Fraternal twins would not share any more genetics than any other sibling pair, so can range from very similar in appearance to very different, the same way some siblings look very similar and others quite different.

 

[DaveC426913]

The other thing that is common these days is embryo transplant. Which means, again, no more similarity than siblings. In fact, they are simply sibs that are artificially brought to term simultaneously.

How old is the mom? More than, say, 35 years older than the kids?

 

[Danger]

It's been so long (+/- 40 years) that I honestly can't remember whether I met them or only read about them, but there were a couple of girls who were born as twins with 2 different fathers. I don't know whether it was the result of a three-way or just a couple of different partners very close together chronologically. Unfortunately, my sex education is of the back-alley variety, so I'm not too sure about the medical aspects of that situation.

 

[J77]

It's been so long (+/- 40 years) that I honestly can't remember whether I met them or only read about them, but there were a couple of girls who were born as twins with 2 different fathers. I don't know whether it was the result of a three-way or just a couple of different partners very close together chronologically. Unfortunately, my sex education is of the back-alley variety, so I'm not too sure about the medical aspects of that situation.

I'm sure I heard a news story on something like this just last week...

 

[fleem]

Hope this wasn't already pointed out, but on a side note apparently it is possible for two babies to grow in the womb together that were fertilized from ovulations a month apart. Its called Superfetation.

 

[Moonbear]

Hope this wasn't already pointed out, but on a side note apparently it is possible for two babies to grow in the womb together that were fertilized from ovulations a month apart. Its called Superfetation.

No, it hasn't been mentioned yet, and that's a good point. It's rare, but indeed, does happen.

 

[pivoxa15]

Someone mentioned that non identical twins look as differently to each other as siblings born some time apart. I don't believe it!

WHy are some twins identical and some not? THis question may shed light to the above.

 

[fleem]

Someone mentioned that non identical twins look as differently to each other as siblings born some time apart. I don't believe it!

WHy are some twins identical and some not? THis question may shed light to the above.

The eggs that the mother produces have different combinations of genes from the mother--each egg has a different set of genes. Likewise The sperms that the father produces have different combinations of genes from the father. So when one egg and one sperm unite, they make a unique individual that is NOT an exact copy of either the mother or father.

Usually just one egg is released from an ovary. After it is fertilized by a sperm it begins to divide into more and more cells and grows into a baby.

Sometimes, though, more than one egg is released and each gets fertilized by a different sperm. These grow into twins which are not identical. Since each baby grew from a separate egg+sperm combination, they are no more similar than their other brothers or sisters born years earlier or later.

However, sometimes AFTER a single egg+sperm are combined, when the cells start to divide to make a baby, some of those early cells don't stick together well and break away. Now you have two or more clumps of cells that came from the SAME egg+sperm! So the babies that grow from each clump are identical.

 

[Moonbear]

Note that even identical twins often look a bit different, especially as they get older. That's because some of our appearance is not due to purely genetic factors, but some environmental factors, i.e., how much weight we gain, sun exposure (I have cousins who are identical twins and look very little alike as adults...one loved going out in the sun as a teen, and the other pretty much stayed indoors, so one has a lot of sun damage, wrinkles, freckles, and the other doesn't), and even hairstyle can make you look pretty different.

 

[pivoxa15]

Note that even identical twins often look a bit different, especially as they get older. That's because some of our appearance is not due to purely genetic factors, but some environmental factors, i.e., how much weight we gain, sun exposure (I have cousins who are identical twins and look very little alike as adults...one loved going out in the sun as a teen, and the other pretty much stayed indoors, so one has a lot of sun damage, wrinkles, freckles, and the other doesn't), and even hairstyle can make you look pretty different.

Fair point.

 

[pivoxa15]

The eggs that the mother produces have different combinations of genes from the mother--each egg has a different set of genes. Likewise The sperms that the father produces have different combinations of genes from the father. So when one egg and one sperm unite, they make a unique individual that is NOT an exact copy of either the mother or father.

Usually just one egg is released from an ovary. After it is fertilized by a sperm it begins to divide into more and more cells and grows into a baby.

Sometimes, though, more than one egg is released and each gets fertilized by a different sperm. These grow into twins which are not identical. Since each baby grew from a separate egg+sperm combination, they are no more similar than their other brothers or sisters born years earlier or later.

Still, eggs produced within a period of time can be different to eggs produced at a later time. Same as sperms. So non identical twins can still be more similar than to siblings born years apart? Say 10 years would be a noticable difference.

This raises the question: Is it true that the sperm and egg 'quality' decline as one ages? Although someone define quality as I don't know how to. If so when is the peak times for male's sperm and female's egg?

However, sometimes AFTER a single egg+sperm are combined, when the cells start to divide to make a baby, some of those early cells don't stick together well and break away. Now you have two or more clumps of cells that came from the SAME egg+sperm! So the babies that grow from each clump are identical.

That would be much more rare? How rarer compared to non identical twins?

 

[fleem]

Still, eggs produced within a period of time can be different to eggs produced at a later time. Same as sperms. So non identical twins can still be more similar than to siblings born years apart? Say 10 years would be a noticable difference.

This raises the question: Is it true that the sperm and egg 'quality' decline as one ages? Although someone define quality as I don't know how to. If so when is the peak times for male's sperm and female's egg?

You're exactly right about egg and sperm quality being related to age of the parents. My guess is that the ideal time physically is probably between age 17 and 34. There's the mother's ability to carry the baby safely, of course, and most damage to genes occur as a mother approaches mid 40s. Father's sperm health also declines, but more gradually--that's why we still sometimes hear about 80-year-old fathers. I did recently read about certain types of defects actually being more common with very young mothers, but now I can't remember the details.

Of course, the differences in children that are related to age of parents isn't really a matter of benign forms of similarity or differences like hair color, build, and so on. Those difference are caused strictly by which of the mother's genes happened to end up in the egg that was used and which of the father's genes happened to end up in the sperm that was used. Those things are not related to age of the parent. The age of the parents affects only the probability of birth defects and gestational health of mother and baby.

For eggs, they are all created when the the mother is in HER mother's womb. For sperm, they are created within months of being used (older ones just die). The mother's eggs degrade over time and the father's specialty cells that produce sperm also degrade over time. Also various toxins collect in everyone's body over the years (like xenoestrogens) which damage the reproductive efficiency and reliability, cause birth defects and bad fetal health, and also cause many other common life-threatening problems in the adults, or in a baby when it grows up. So the only difference in later-born children really has strictly to do with the probability of birth defects rather than how similar they look to siblings near their age.

On a side note, this gives me a chance to propound that the xenoestrogen problem is really bad and people need to take notice. The ill effects of xenoestrogens don't show up for years, sometimes decades--so we are only now noticing it. Xenoestrogens don't biodegrade much at all, and they collect in fatty tissues (so they build up in the food chain). Studies over the last couple decades are now proving that they are the cause of a myriad of life-threatening problems. They are the cause of the 50% drop in men's sperm counts of the last few decades, damage to sexual development in children, and they are the cause of most breast, prostate, and ovarian cancers that occur! Xenoestrogens come from herbicides, insecticides, cosmetics, plastics food containers, certain common solvents and emulsifiers, synthetic clothing (through the skin and when the lint is inhaled) and other places.

That would be much more rare? How rarer compared to non identical twins?

Looks like the probability of having identical twins is about 1 in 280, fraternal twins 1 in 125.

 

[pivoxa15]

Birth defects being the genes not properly transcribed and carried out?

When that happens at a minor level, the effects will show later in the baby's life?

What do you mean by degrade of sperm and egg?

fraternal twins being twins with different fathers?

 

[jim mcnamara]

fraternal twins are dizygotic twins - twins formed from two separate eggs combined with two separate sperm. Creates two individuals. Not necessarily the same sex and definitely not with the same genes.

identical twins are monozygotic - formed from a single egg combined with a signle sperm.
The zygote divides forming another identical zygote. Each one (total of 2) goes on to form a separate individual. You get 2 people of the same sex with identical genes.

-- just to clarify. You guys are throwing terms around and it is confusing to other readers.

 

[fleem]

Birth defects being the genes not properly transcribed and carried out?

When that happens at a minor level, the effects will show later in the baby's life?

What do you mean by degrade of sperm and egg?

fraternal twins being twins with different fathers?

"Birth defects" simply means any wrong development in the baby, whether caused by genetic damage, trauma (injury), or chemicals.

By "degrade" I mean genetic damage or possibly weak sperm (that can't swim well).

Fraternal twins mean twins that aren't identical.

The older the parent, the more likely the genes in the egg or sperm will be damaged (because cells have had longer to get damaged), and thus the less likely a fetus will be viable and if it does grow the more likely it will have genetic defects. Its a higher probability but still fairly low. Down syndrome is the classic example--the probability increases substantially as a mother gets into her 40's, but even then its something like 1/600 if memory serves me. Typically genetic damage is apparent early on--its affects aren't necessarily that delayed or hidden.

Xenoestrogens typically won't cause genetic damage in a fetus, however they can cause genetic damage in that fetus's offspring (by messing up the fetus's ability to create good sperm or eggs)! Xenoestrogens alter the development of the baby just like too much estrogen would. They collect in people and so are more dense in older people. Xenoestrogens cause feminization of male babies, damage to the fetu's ability to create sperm or eggs, early puberty in girls, and other things. They also pretty much explain why men's sperm counts have dropped so profoundly in the last few decades. Xenoestrognes in adults are the prime cause of some common cancers and other things.

Here's a good starting point to see all the studies that have been done that clearly show these things are happening. Also you'll see how doctors often treat patients with xenoestrogens thinking they will help certain problems when they simply exacerbate them (like menopausal symptoms). (Note that the pharmaceutical companies only push non-natural substances because they aren't allowed to patent natural substances, and that pharmaceutical salesmen are often the only source of information a doctor has because doctors are too busy to read the journals propounding the studies!)

Here's the link:
http://www.johnleemd.com/store/resource_references1.html

.

 

[dkmacmillan]

It takes some time for ovulations to resume after one gives birth, though that time varies among individuals and whether or not one is breast feeding. But, still possible to have a baby born in January and another in December (especially if the second is a bit premature).

Even if it's the normal way that a woman recovers from childbirth this isn't always the case. I have two cousins who are roughly nine months apart. I don't remember their birthdays exactly but I know it's nine months & a week or two. Lol, the doctor told my uncle to let the stitches heal next time. Anyway, to answer pivoxa15's original question no, two babies born in the same year don't have to be twins.

Still, eggs produced within a period of time can be different to eggs produced at a later time. Same as sperms.

Actually women are born with all the eggs they will ever have, not 100% sure of the number but I think it's in the neighborhood of 40,000 eggs.