Marriage and fatherhood have both been shown to decrease testosterone levels

Excerpt of an Article in Zero Hedge (a Financial blog)

Newsweek reported in 2009:

Monkeys that see sexually active females register as much as a 400 percent jump in testosterone (nature’s own performance-enhancing drug) promoting lean muscle and quick recovery times, according to the Yerkes Center for Primate Research at Emory University. In humans, German researchershave found that just having an erection is enough to spur testosterone levels. it makes no difference whether a man is watching sex on a screen or having it in real life, his testosterone levels will go up. Just having an erection, in fact, is enough to spur production.

Such findings, along with work that shows family life to be a drain on testosterone levels, prompted Rutgers University sex researcher Helen Fisher to advise this month that males in the “captivity situation”-her term for married with kids-”go on the Internet and look at porn” as a kind of hormone-replacement therapy. “[Porn] drives up dopamine levels, which drives up your testosterone,” she tells NEWSWEEK, while kissing your wife or hugging your kids drives it down.

Indeed, marriage and fatherhood have both been shown to decrease testosterone levels.

Other stuff to Boost Testosterone Levels.

• six-second bout of sprinting increased serum total testosterone levels.
• Numerous studies have shown that resistance training is a powerful stimulant for testosterone production. So – if you are physically able – be sure to lift heavy things every now and again
• The JAMA  reports that lack of sleep dramatically lowers testosterone in healthy young men.
• Studies in the the Journal of Hormones and Behavior, the European Journal of Applied Physiology show prolonged stress produces cortisol reduces T levels. So take breaks and play sports, go for a walk, meditate, do yoga or do whatever else de-stresses you.
• Vitamin D (sunlight) positively correlates with testosterone levels in men, according to the Journal of Clinical Endocrinology and researchers at the Medical University of Graz in Austria.
• Eat Monounsaturated and Saturated Fat. See this, this and this.