A few days before the birth of her second child, Angela V. of Pennsylvania discovered a troubling fact: Although her baby’s biological father was her live-in boyfriend of two years, under Pennsylvania state law, her not-yet-ex-husband — whom she hadn’t been intimate with for more than a decade — was considered the baby’s legal father.

“I had no idea!” Angela says. “I was talking about last names with my friends and mentioned that, legally, I still had my ex’s last name because we had never actually divorced. That’s when one of my friends told me that my boyfriend wouldn’t be considered the legal father because I was still technically married. I didn’t believe her at first, but it turned out to be true.”

Sure enough, once the baby was born, Angela discovered that she had to have her ex sign a waiver stating that he was not the baby’s biological father before she could list her boyfriend on the baby’s birth certificate.

“To be honest, I hadn’t even considered that this would be an issue,” Angela says. “My ex and I have been legally separated for 12 years, but we were both too stubborn to pay for a divorce. I know that we should have taken care of this years ago, but I guess I’d sort of stopped thinking about it. In my mind we were divorced, even though we had never made it legal.”

When she started dating her boyfriend two years ago, Angela told him she was separated but not legally divorced. Still, when the two discovered Angela was pregnant, the last thing on their minds was the legal status of the father.

“When I called my ex and asked him to sign the waiver, I thought he was going to have a heart attack,” Angela says. “He texted me all day, to make sure he wasn’t going to be responsible for another man’s baby. If I’d known, I could’ve warned him. But, on the bright side, this did prompt us to go ahead with that divorce!”

Angela’s situation is not as unusual as it might seem. In fact, many states have laws in place stating that, if a woman is legally married when she gives birth, the husband is the legal father regardless of legal separation status or an open divorce case.

In legal speak, the “presumed father” is the person recognized under state law as the legal father of a child. If a man is legally married to the woman giving birth — even if they are divorcing — he is considered by most states to be the “presumed father.” Some states have made provisions for legally separated couples. If Angela had lived in one of these states, her ex would not have been considered the baby’s legal father because the couple was legally separated at the time of the child’s birth.

In other states, Washington State, for instance, a woman who is legally married but having another man’s baby can ask the biological father to sign a Paternity Acknowledgment following the baby’s birth. However, the woman’s legal husband must also sign a Presumed Parent’s Denial of Paternity waiver, or the biological father’s Paternity Acknowledgment will be considered invalid.

Of course, it is certainly plausible that a woman who is legally separated or divorcing may be giving birth to her husband’s biological child. In this case, the state laws are set up to protect both mother and baby financially by presuming that the husband is the legal father and therefore still legally responsible for the child’s well-being. If the presumed father denies that he is the biological father, the mother can file a petition with the court to determine paternity through DNA testing.

If you find yourself in a situation similar to Angela’s, look up paternity laws in your state before you start to worry. And remember, knowing ahead of time can alleviate a lot of confusion.

“I wish I’d known about this months ago,” Angela says. “We could have finalized the divorce, or I could have, at the very least, warned him that this was the case. He would have been prepared and I wouldn’t have had to deal with him freaking out on the same day that my son was born.”