In my math world novel these numbers have come to life and they have 10 operational chromosomes( +, -, *, /, ^, arrow arrow(tetration), nth root, logarithm, super root, and super logarithm). They also have 4 sex chromosomes each of which can be X or Y. With these sex chromosomes it is like this: XXXX = female XXXY = male XXYY = hermaphrodite(bi-fertile at that meaning that both of its reproductive systems can produce gametes) and XYYY = male As far as whether they are overweight or underweight it never gets to that point in the long term. For the potentially overweight case the brain sends a signal to all parts of the body saying "Use the fat reserves and make them top priority for energy" This accelerates fat metabolism by quite a bit and ATP production by a lot(with more than 100 ATP produced per fatty acid). This causes there to be less adipose tissue because there are less fat reserves and more adipocytes undergo apoptosis which makes them still be at a healthy weight. For the potentially underweight case the brain sends a signal saying "increase muscle mass and store glycogen as fat". It then sends another signal to another part of the brain telling the light person to eat. This increases digestion and the person is still at a healthy weight. Anyway to get to the point, these numbers have a whole chromosome with lots of genes that determines their size including an overall height gene. Some genes take priority over others as far as determining size. However this is complex as well because for example 2 L alleles in the heart gene will cause the lungs to be large which will cause the chest to be large which will cause the person to be tall. However 2 L alleles in the ovary gene will only change the size of the ovaries. Also 2 L alleles in the brain gene will cause the skull to be large which will cause the head to be large which will cause the person to be tall. This isn't the complex part of the priorities. What makes it complex is when the Lungs, Heart, Brain, Muscles, Bones, and Skin genes have different combinations of alleles since these are all high priority genes. These have 15 possible alleles. They are: XXXXXXS XXXXXS XXXXS XXXS XXS XS S M L XL XXL XXXL XXXXL XXXXXL and XXXXXXL XXXXXXS is the natural 0th percentile and XXXXXXL is the natural 100th percentile. To get the offspring size the mother size and father size are added up for most of the possible combinations. This means that the sizes are like positive and negative numbers since S+L=M, XS+XL=M, etc. This is like incomplete dominance. However for combinations that when added up would lead to something smaller than XXXXXXS or larger than XXXXXXL the larger size dominates. This is like complete dominance with a dominant allele and a recessive allele. Would this be complex dominance since there are 2 kinds of dominance for the same alleles?