Ok, what legal actions can be taken on someone that is 20 and gets his 16 year old girlfriend pregnant, if it was willing?

I don't think even if she was willing it will matter because of the age difference. It will probably be up to the court and whether her parents push the issue.

I could be mistaken, but I thought it depends on the state... 16 is OK in some states, not in others.

Yeah that is true. What state do you live in and I can find out for you :)

I see you put Indiana in another post... the age of consent there is 16, so it would now depend on how far along you are... and how far past 16 you are.

That is true. If you got pregnant while you were 16 it is legal, if you were 15 when you got pregnant it isn't.

Also, it is illegal if he was in a supervisory position to you.