A small study of men who were conceived in the 1990s using a now common fertility treatment suggests that they are themselves less fertile.

Intra-cytoplasmic sperm injection (ICSI) is a technique that injects sperm directly into an egg to fertilise it. This method is commonly used to overcome various types of male infertility – including low sperm count, abnormal sperm, or sperm that doesn’t move well – and was used in about half of IVF treatments using non-frozen embryos in the UK in 2013.

Because the method can allow non-motile sperm to create an embryo, scientists have suspected that it can pass genetic causes of infertility to the next generation. Now there is some evidence that this could be the case.

Comparing 54 men who were conceived using ICSI with 57 men whose parents conceived naturally, Andre Van Steirteghem at the Vrije Universiteit Brussel in Belgium and his colleagues have found that the ICSI men had almost half the sperm concentration of the control group, and a two-fold lower count of motile sperm.

“These findings are not unexpected,” says Steirteghem. “Before ICSI was carried out, prospective parents were informed that it may well be that their sons may have impaired sperm like their fathers.” These parents still decided to try the technique, thinking that their sons could themselves use ICSI if necessary, he says.

Lower Sperm Counts

The ICSI men were all born between 1992 and 1996, during the early years of the technique. On average, they were almost three times more likely to have sperm concentrations below the World Health Organization’s definition of normal. “Whilst these young men may have lower sperm counts than the general population, they may still be able to father children without treatment,” says Adam Balen, of the British Fertility Society.

Steirteghem stresses that these results show a correlation, not a causal link. While genetics plays a role in male infertility, other factors may also interfere, he says.

Allan Pacey, at the University of Sheffield, notes that the sperm quality of the fathers in the study didn’t always match that of their sons. “It doesn’t automatically follow that ICSI-conceived males will always have the poor fertility seen by their fathers,” he says.

Source: New Scientist