yes you can, although i am not 100% sure how yet, i know that if a man gets abducted by an alien they get pregnant. If you want the aliens they are in The Sims 3 season expansion pack.
Chat with our AI personalities
You can't. Female Sims in Young Adult and Adult life stage can get pregnant. However, there might be a special cheat available to make a Teen Sim pregnant.
Can't, unfortunately
As far as I know, there has never been a teen pregnancy cheat in any of the Sims
They are 3-4 sim days long.
If you are talking about being pregnant while in the university, then the answer would be a no. However, if you are talking about being pregnant at your hometown (Sunset Valley, Twinbrook etc), then your sims can get pregnant.