Her mother has died in a tragic pool accident! Basically the only pregnancy related want Juan got was to talk to Lulu's tummy or something like that, and he wasn't able to do it before Juanita was born, and Lulu turned elder the instant after Juanita was born, so Lulu HAD to go!!! Juan had that slot stuck for Juanita's entire life up to YA!!! So since he really wanted it and his elder wife couldn't give it to him, Lulu had to die. Thanks for those on the forum who finally revealed the secret to successfully making a Sims 3 pool death happen!