According to an interesting study, males that have a long beard and long hair may have smaller testicles. The study describes how male primates including humans may only have enough energy to grow big testicles or long hair and beard to impress the female counterpart. The study includes all kinds of male primitive, even men. The study further says that males may face stiff competition as they try and attract potential mates and therefore men with smaller testes may grow a long mane to attract women. The researchers studied testicle sizes and looks of 100 species and found out that primates only have the energy to develop either testicles or their hair and beard to enhance their looks. Men who struggle to grow their facial hair may have bigger testicles that men with long beards and hair. They consider it an "evolutionary dilemma" when it comes to their genitals. Researchers believe that a male "can be well-adorned or well-endowed, but it's hard to be both." Beard Bouquets: Men Handsomely Sporting Flowers in Their Beard is One Fun Fashion Trend.
Primatologist and study co-author Dr Cyril Grueter, from the University of Western Australia, said to Daily Mail that testicle size varies enormously and is linked to a male's appearance. She further said: "Some [primate] species sport flamboyant accoutrements such as beards, manes, capes and cheek flanges, and various shades of colour in their faces and fur. Others are pretty drab and look more like your Mr Average. This finding clearly shows that you can be well-adorned or well-endowed, but it's hard to be both."
Researchers explain this with the theory of overcompensation in males. The men who are poorly endowed submit all their energy into attracting mates by working towards their looks, usually beards and long hair and have none left to invest in their genitalia.