The Bizarre Reason Some Men Have Less Sperm Than Others

October 6th 2016

Lucy Tiven

A new study has delivered some unfortunate news about sperm counts for men who were conceived through in vitro fertilization.

Men who were born as the result of a particular kind of IVF — called intracytoplasmic sperm injection, or ICSI — produced about half the amount of sperm as men who were conceived naturally, according to the study by the Centre for Reproductive Medicine at Belgium's Vrije Universiteit Brussel, published in the journal Human Reproduction.

Such men also had half the amount of motile sperm — sperm able to swim well enough to reach an egg — as a control group.

"These findings are not unexpected," lead author Andre Van Steirteghem told The Guardian. "Before ICSI was carried out, prospective parents were informed that it may well be that their sons may have impaired sperm and semen like their fathers. For all the parents this information was not a reason to abstain from ICSI because, as they said: 'If this happens, ICSI can then also be a solution for our sons.'"

Researchers made the discovery after comparing the sperm counts of 54 men conceived using ICSI to that of men conceived the old fashioned way.

What is ICSI?

ICSI is an IVF procedure in which a father's sperm is injected directly into a mother's egg before the egg is placed in her womb.

This differs from other IVF treatments in which an egg is placed in a dish with multiple sperm, according to the U.K. Human Fertilisation and Embryology Authority.

ICSI is often recommended for men with low sperm counts or with abnormal sperm and for couples who have used other IVF procedures without success.


About 63.5 percent of 2007 IVF treatments in the U.S. made use of ICSI, according to the Pacific Fertility Center, a Bay Area fertility clinic.

IVF treatments aren't the only medical reason a man's sperm count may be low.

Cancers, celiac disease, hormonal imbalances, chromosome defects, and numerous other medical conditions have been linked to sparse sperm counts, according to the Mayo Clinic.

Studies have also linked low sperm counts to exposure to cleaning chemicals and other pollutants, spending time in hot tubs, and a sedentary lifestyle.