This isn’t necessarily on their profile, but when speaking to single parents I have noticed its a huge red flag if they badmouth the biological father/mother of their kids. That usually means they’re still bitter about whatever shit happened between them that caused them to separate, and that they most likely do not get on. Not only do you have to deal with a child that’s not yours, you gotta deal with the other parent’s drama and bullshit too.

Source: before I was CF I dated a single dad and deeply regret it. He badmouthed his kid’s mom and for good reason, but I didn’t wanna deal with the extra baggage. She was a shitty mom and started fights with the guy a lot.