Yes, marijuana has no affect on the male sperm count, there have been reports that it lowers your sperm count, but however this is not confirmed.
Doug Benson, a famous comedian made a move to document the affects of marijuana to his health, sperm count, etc; entitled "Super High Me" (a spin off name taken from the "Super Size Me") Where he stayed high on marijuana for 30 days (having a full medical exam before and after) and in his tests his sperm count shot up by huge numbers.
However your question entitles "smoking" as the key way of administration, smoking in any form can lower your sperm count, but he would have to smoke an insane amount of pot each day until the tar starts to kill his sperm off.
Hope this answered you question, and BE SAFE!
Always use a condom!!!!