Can drugs such as cocaine have any effects on sperm count or quality of sperm?

Yes: Cocaine use has been found to lower sperm counts, reduce the sperms' motility and increase the number of abnormal sperm. Using Cocaine just before conceiving has also been linked to birth defects in children. Marijuana, cigarette smoking and alcohol can also negatively affect your fertility.

Yes, both: They not only cause a reduction in sperm count and increased number of abnormal sperm, as well as reducing sperm motility, they also can cause changes in the dna of the sperm nucleus which appear to be associated with increased adhd and other problems in offspring. In addition, there was even a study that showed tiny molecular amounts of Cocaine in the sperm itself, which can increase birth defects.