Weed..

So my boyfriend and I have been dating for a little over a year now and we didn't start having sex until we were 7 months in. He smokes weed alot and i hate it so i hate that he does it. I am kinda worried about later on in the future that if he keeps smoking than it will effect his fertility. Is this true? Can weed effect his sperm count? Anything would be greatly appreciated. Thanks guys :)