1) how long does boy sperm last
sperm in general an average of 5 days inside the body. Boy sperm swims faster and dies first, so like 2-3 days.
2) how long does girl sperm last
5 days.
3) how long does sperm last out side the body.
You mean open to the air? A couple of hours? Or closed up, same as in body. Sperm is stored refrigerated, so temp doesn't have that much to do with it, I wouldn't think. Or 15 years if frozen. But conception has occured with 18-20 year old sperm, but not likely.
4) once ovulation has begun how long have we got to get pregnant.
Average of 12 hours, maximum of 24 hours.