The US already supports it, at least socially. One of my good friends actually acted as a surrogate mother for two gay male friends, and I support her decision whole-heartedly.
Many children grow up abused, neglected, undereducated, underfed, and worse -- those are the real child-welfare issues, not the sexual orientation of parents. Gay people are just as capable of raising a child in a healthy, nuturing, loving environment as straight people -- perhaps even more capable, since adoption is much more difficult than conception.
It can easily be argued that the first five years are the most important years of a child's development -- long before the child will even have a concept of what it means to be "gay." Once the child is old enough to understand sexuality and the meaning of being "gay," he or she will be old enough to handle the implications.
Despite prevailing ignorance, studies have shown that children raised by gay couples are no more likely to become gay than childen raised by straight couples -- so, even if one is anti-gay for some kind of moral reason, one still has no justification to denounce gay couples raising children. It's not going to spread homosexuality, or any such nonsense.
Children need food, shelter, care, attention, education, love, openness, guidance, a proper measure of freedom, and more. They don't need straight parents. If a gay couple is capable of providing a healthy environment for a child, it is unconscionable to deny them the opportunity.
- Warren