Perhaps. Opioid drugs lower testosterone in men and interfere with the menstrual cycle in females; both can contribute to infertility. Thc also reduces testosterone and sperm counts but I am unaware if it will lead to menstrual problems without other co-occurring medical diseases. Use of stimulant drugs and/or alcohol may lead to malnutrition which may reduce fertility as well.
Yes. Abuse of steroids, cocaine, alcohol, methamphetamines, opioids, and cigarette smoking (see elshal; clin biochem:2009) have been reported to negatively impact male fertility.