Sex, Preganancy and Sperm Life

Patient: If the last time my girlfriend and I had sex was a little over 2 years ago (mostly protected but sometimes I would pull out before ejaculation) what is the likelihood she could still become pregnant?

Doctor: We believe sperm can only survive 48-72 hours after ejaculation.  It would not survive for 2 years on any surface unless s it was preserved by freezing at a sperm donor clinic.