Recently I was talking to my mum and quite casually she asked me 'you know about your Uncle ____'s other kids don't you?' to which I replied 'huh? other kids?' Turns out that one of my uncles (who I always thought was one of the more normal members of my family, which isn't saying a lot) has FIVE other kids besides the two that I knew already as my cousins, who came about because he has a thing for donating sperm. This is despite being married with kids for many years (divorced now), and my then aunt was fine with it apparently! This has weirded me out a bit, just thinking that if I put it about quite a bit I could've slept with my cousins and not realised! Anyone think this is a normal situation?