One of them is a lesbian

Bob sends this excerpt from the Dilbert Newsletter 60.0.

My nephew, a freshman in college, attended a meeting in his dorm in which everyone introduced themselves and shared some personal information to get acquainted. My nephew introduced himself and mentioned that he has two moms. An Induhvidual looked at him and said, in all seriousness, “So… does this mean that one of them is a lesbian?”

It sounds ridiculous, but the nephew does not have "two moms". He has one mom, and that mom is probably not even really a lesbian. She was probably married to his dad who turned into a man-hating feminist.