If someone joined here with the name "sperm", I would not accept it, it smacks of troll. Also due to the forum being PG-13 via it's sponsors, being crude is not allowed unless the word used is medical and related to a medical conversation.
I would not accept any kind of genital related related username as you don't know where it is going to end before it all starts getting crude.
We also allow only one account, if someone has two or more they get a warning and the other accounts deleted.
These subjects are mentioned in the rules here.
I'm aware of SAS being stricter than here and your own forums being far more relaxed than here, I guess everyplace on the net is run different.