Yes! Only this season, they have brought in 4 new teen moms from MTVs 16 and Pregnant season 2. Weather or not they will still film the original four, I dont know.
Unfortunately you can not marry teens in sims 3. :(
Teens can do anything an adult can except marry, woohoo, or get past level 3 of their career.
you have "whoo-hooo" a few times and eventually u will have a baby