My bf smokes weed almost every other day. does that lower his sperm count? & his doc said it'll b hard 4 him to have kids.didnt cum in me but pre cum

Yes: Mj lowers sperm count, but is not a birth control method by any means. Sperm can be found in pre-ejaculate (and it only takes one). Perhaps it was a value judgement by the dr about heavy weed smoker? Use condoms to prevent pregnancy and any other undesired "surprises, " some which may last a lifetime.

Very Possibly: Mj is one of the worst drugs that affect sperm. Our experience has been a decrease in count motility and morphology. Often these effects are longstanding even if the male quits smoking. We would advise to discontinue this habit for better pregnancy chances. It is not an absolute sterilizing substance though, otherwise the human race would have ended in the 60's? Good luck.