No, they cannot.
Chat with our AI personalities
No. Your sims need to be one of the following: Young Adult - Any Tattoo Adult - Any Tattoo Elder - (Unknown)
If you mean on Sims 2 then you have to have the University expansion pack, then make a teen Sim go to college and they will turn into a young adult Sim. If it's on Sims 3, then I am not sure, sorry.
Yes, your sims have a life span which you can change the length of in options. They have different stages of life for a certain amount of time: baby toddler child teen young adult adult elder
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.
The teen and the child will be taken by the adoption service.