When my kids were born I didn’t have to undergo a DNA test to prove that I was the biological father of those kids. They just wrote down my name.
In just about all cases you can become the legal father of a newborn baby just by the mother stating that you’re the father, and you don’t deny it. If there is no disputation of paternity then the matter is closed.
The establishment of paternity has a long legal history that mostly predates DNA tests. The legal principle is generally that when a married woman has a child, her husband is the legal father of those children. The courts aren’t going to dig into who had sex with who, if you’re the husband you’re the father, and if your wife is fooling around then that’s your problem, not the court’s problem.
Also there’s generally a “no backsies” rule. A man generally has a limited time to dispute paternity, and if he accepts paternity that’s it, he’s the legal father, no matter what a future DNA test might or might not show. Paternity is a social and legal matter, not a biological matter.
Yes, you can be assigned legal paternity for a baby if a DNA test shows you’re the biological father, even if you have no interest in the kid. But that’s because society has an interest in making sure children are taken care of and that costs money. And so we will force you to care for that child, because otherwise the rest of us will have to do it. Sure, you don’t want to take care of the brat, but neither do the rest of us, and you’re the one who created it, not us, so it’s on you.
Yeah, that source isn’t clear as to how hard that would be to do. Here’s a bit from Maryland, suggesting that in Maryland, it is possible to legally rebut that presumption, but really really hard:
True for maternity as well. Our son was born via egg donation, hence my wife is not his biological mother. But she is on the birth certificate, and is his legal mother.
Just think, in 18 years there’s going to be a cohort of new citizens who are going to have a very hard time getting a government-issued photo ID because of this. And they’re going to be required to show that photo ID in order to be allowed to vote.