Sons could inherit their fathers’ infertility through common IVF technique


A fertility technique used by thousands of British couples could lead to sons inheriting their father’s infertility, a new study suggests.

Tests on a group of men who were conceived using intra-cytoplasmic sperm injection (ICSI) because their fathers were infertile revealed that they too ended up having low sperm counts and poor moving sperm.

Researchers at the Centre for Reproductive Medicine at the Vrije Universiteit Brussel (VUB) in Brussels, which pioneered ICSI, said the findings showed a degree of “sub-fertility” had been passed on from fathers unable to conceive naturally to their sons.

“These findings are not unexpected,” said VUB’s Professor Andre Van Steirteghem.

“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.”

An egg cell being fertilised in Belgium.
An egg cell being fertilised in Belgium. Credit: PA Wire

ICSI involves a single sperm being injected directly into an egg.

As part of VUB’s study, data was collected from 54 young men who had been born between 1992 and 1996 – the early years of ICSI. The results were then compared with 57 men of a similar age who were conceived naturally.

Blood and semen tests on the sons showed they had almost half the sperm concentration and a two-fold lower total sperm count, and total count of motile sperm than men conceived naturally.

Furthermore, men born using ICSI were almost three times more likely to have sperm concentrations below 15 million per millilitre of semen, which is the World Health Organization’s definition of normal.

Prof Van Steirteghem pointed out that even though the sons had lower sperm counts and less motile sperm, the results did not exactly match those of their fathers.

The study shows that semen characteristics of ICSI fathers do not predict semen values in their sons.

It is well established that genetic factors play a role in male infertility, but many other factors may also interfere. Furthermore, correlation is not the same thing as causation.

– Professor Andre Van Steirteghem, Vrije Universiteit Brussel

In 2013, there were 37,566 embryos transferred using ICSI treatment in the UK. About half (52.6%) of IVF treatments with fresh embryos in 2013 involved ICSI.