We all know the jokes. "I look like my dad, my sister looks like my mom, and my brother looks like the mailman." That phenomenon of a woman getting knocked up by a man who isn't her husband and then passing the kid of as being his is out there. For convenience sake, we'll call the unwitting biological father the "ghost father."

I'm curious if there's any research on this topic. Are there any patterns as to who the ghost father ends up being. Does the father (or tricked father) know him? It he a one-night-stand? Someone the mother had a long-term affair with? I'm curious if there are any patterns.