In my "canon" games, I always make Don marry Cassandra. Then they have twin boys, and they always look a lot like their dad.
In a past game, I cheated and resurrected Darleen using the phone. She and Darren had a daughter. Then I killed her as an elder when I got bored, before restarting Pleasantview. In my current game, Darleen remains dead and Darren is over Cass. All he has is Dirk, Lilith, and his grandson.
I created an alternate Pleasantview though, and here Darren marries Cassandra, who is pregnant with Don's child. Don had a falling out with all his girlfriends because they all caught him cheating, and he ends up marrying Malcolm Landgraab. Then he sleeps with Dina one last time before fully committing to Malcolm and becoming a Fortune sim. But Dina also ends up pregnant, and she's bound to marry Mortimer soon. In my head, she's just going to tell Mortimer it's his.
I have to admit that my alternate timeline can be fun in its own way.
Also, these are the twins, Nicholas and Benjamin. Cass and Don make handsome kids. :D
http://i60.tinypic.com/2uhbwbc.jpg
