I don't know , I think excessive masturbation throughout the teenage years could cause some hormonal imbalance , maybe a spike in Testosterone or other hormones. Therefore resulting in more DHT being produced earlier (not saying this is true). The guys who are prone to male pattern baldness but wouldn't have got effected by it until they were in their late 20's/30's start a lot earlier. There is no proof of this because there has been no experiments done. When I say excessive masturbation , I mean 2-3 times a day from the age of 14 upwards.. Yes , I was that horny and believe this caused some sort of hormonal imbalance or deficiency of some sort which in turn caused me to begin my hair loss cycle years earlier. Of course the zinc released during ejaculation would never have any time to replenish and other hormones would go crazy ... adrenal fatigue etc..
I'm talking about excessive masturbation here , not masturbation. I'm saying what effects it could have in the teenage years.. Excessive masturbation is no different to sex if sex is done excessively too..(2-3 times a day for 5-6 years) but who is that lucky..
As for the monks , they are old and therefore follow normal male pattern baldness protocol. When I say excessive masturbation could contribute to guys balding earlier , I mean young guys who excessively masturbated from the age of 14 upwards could have caused their bodies to produce more/less of certain things to speed up their male pattern baldness.
Now don't flame me for this but when I look back on photo's of the 50's etc men seemed to keep their hair a lot longer.. It seemed men wouldn't start losing their hair until their late 30's , the odd teenager would become a NW2. In my school now there are tons of balding teenagers.. Maybe brought on by the change in easy access to x-rated material? I had access to the internet whenever I wanted from 13 onwards privately.. I'm losing my hair since I was 17 , was this because of excessive masturbation? Who knows?
Not saying any of this is true , just theoretical..