Default account creation
A user can connect, create an account, and carry on as usual. This would be what most people expect when they create an account.
Two existing users, who have a total online time (age) over a certain limit (TBD) can pair up and create a user. When a user creates an account, they're asked for their "birth ID", which is a password (or number) generated when two existing users generate an account together. After a birth, both parents will be unable to give birth again for a period (time being online time).
Whenever a user is created through "birth", their parents statistics are merged, and some mutation is added to form the statistics of the new user. If the two existing users are closely related, then the merged statistics will be very similar, so mutation will affect the outcome more - hence "inbreeding".
Anyway, that's enough gibbering from me for now. I'm off to bed.