Nightmares are not hereditary. We have plenty of things happen in our lives that are more than enough to give us the raw material for nightmares. Nightmares signal the psyche's need to get a message across to our waking mind. That could clearly affect sleep. Aside form that, there really isn't a lot of difference.
Apnea is more common in men by a factor of ten.
But everyone has sleep problems sometimes and it does not seem to me to be mostly gender related. Yes there is conflicting info. No, I don't think it is. 5-HTP is available without prescription. St. John's Wort seems to act in the same way as the SSRI's and keeps Serotonin from being re-absorbed by the system.