Porn has a deleterious effect on society, but decreased serum T isn’t one of them.
Nutrition, weight training, and proper rest are large.
Constant stressors, popping scrips, processed high carb foods, xenoestrogens and phytoestrogens, and lack of sleep and exercise are big contributors.
Actually, research has long shown that sexual intercourse increases testosterone levels. Masturbation has no such effect. Pornography has replaced relationships for a large number of males, with the advent of free internet video porn especially addicting.
Don’t forget high fructose corn syrup in almost every food