This is one of the most common questions that arises when same-sex couples have children. Seattle University law professor Julie Shapiro blogs almost exclusively on this topic. The significance of a genetic connection to the child is a constant theme.
So I was fascinated by last week's LA Times story about the Kincaid project, which involved DNA testing of 147 people named Kincaid. Two brothers discovered they had a different biological father, something they find too painful to discuss. The article quotes studies that suggest 4% of children are not the biological children of the man they consider their father. One man, Don Severs, was able to confirm that his great-great-great-grandfather was a Kincaid who had an affair with the family's housekeeper, who was then married off to a man named Severs. DNA testing can also uncover relatives who were never told they were adopted.
If we DNA tested every child, we would know at birth whether the mother's husband was the child's genetic father. We don't do this. That alone shows that we value some things above biology, and rightly so. At a recent symposium, I asked Brigham Young law professor Lynn Wardle whom he would consider the father of a child born to a married woman but not her husband's biological child. I posed the question with the assumption that the husband wants to raise the child as his own and the biological father wants to raise the child as well. His answer: the husband. He's not going to say that of course for a married or otherwise partnered same-sex couple. But once we set the stage for parenthood based on function, relationship, or anything not biology, we open the door for what the children of same-sex couples already know: biology is neither necessary or sufficient for parenthood.