28.05.2019 by

Mossman-Pacey Paradox Promotes Misinformation About Steroids and Sterility

Mossman-Pacey Paradox Promotes Misinformation About Steroids and Sterility

Researchers alleged that 90% of steroid users will become infertile without highlighting the fact that it is usually temporary.

Dr. James Mossman and Dr. Allan Pacey recently made headlines by describing a so-called paradox in which men use steroids to score more women but end up becoming infertile. The men may look more masculine and muscular but their evolutionary fitness is low.

Mossman and Pacey elaborated on this paradox in a recent letter published in the The Association for the Publication of the Journal of Internal Medicine.

“In evolutionarily blunt terms, no sperm = no babies = low fitness,” Mossman and Pacey wrote. “In other words, many men set themselves an unachievable goal of being both physically and evolutionary fit when using AAS [anabolic-androgenic steroids], and put their masculinity and muscularity in direct conflict.”

Steroid use makes men look more masculine and muscular but disrupts sperm production.

The researchers were baffled that men would use drugs so that they could have more sex even if the drugs decreased their fertility. Of course, women have been using birth control pills specifically to decrease their fertility so they can have more sex for over 50 years.

The researchers followed up with press interviews in which they promoted misinformation and hysteria regarding the fertility side effects experienced by anabolic steroid users. Mossman and Pacey were quick to emphasize the effect of steroids on fertility but they neglected to mention that it was only temporary in most cases.

“I would say more anabolic steroid users are likely to become sterile than you would think – 90% probably,” Allan told the BBC.

However, men who use AAS, just like women who use birth control (steroids), only suffer a temporary disruption in their sterility. Mossman and Pacey failed to point this out.

Anabolic steroids disrupt the hormones that produce sperm in a phenomena known as anabolic steroid induced hypogonadism. This disruption is only temporary. Once steroids are discontinued, sperm production eventually returns to normal. Permanent sterility from steroid use, if it exists, is a rare occurrence.

The evolutionary fitness of most steroid-using bodybuilders is just fine.

  • Gallagher, J. (May 28, 2019). Fertility paradox in male beauty quest. Retrieved from

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