As a generation of children conceived through a type of in vitro fertilization procedure grows up, research is showing that those boys have much lower sperm concentrations and quality when compared to boys conceived the old-fashioned way. These findings came to light in the most detailed study thus far on children conceived using this type of IVF, and they suggest that men who used IVF to conceive may be passing along their infertility to their sons.
Scientists from Vrije Universiteit Brussel in Belgium studied the first group of boys in the world to be conceived using the in vitro fertilization procedure known as intracytoplasmic sperm injections (ICSI).
Today, the most common IVF procedure involves mixing many sperm cells in a petri dish with an egg, until the egg is fertilized. ICSI involves the injection of a single male sperm directly into an egg to effect fertilization.
ICSI was developing during the 1990s to assist infertile men, and it is highly successful. It is still widely used today. Children conceived through this procedure have one thing in common: their fathers had difficulty with fertility. This presents a unique opportunity for researchers.
The Belgian researchers examined sperm samples of 54 young men who had been conceived during the first rounds of ICSI, between 1992 and 1996. They compared these samples to those of 57 male controls conceived naturally. All the men were between 18 and 22 years of age, and were unmarried. Adjustments were made for factors that have an effect on sperm quality, including age, body mass index, and length of time since the subjects had had sex.
The research team discovered that the ICSI conceived men were three times more likely to have lower sperm concentrations than the control group, and four times more likely to have a sperm county below 39 million. Normal sperm count is over 15 million sperm per milliliter, and 39 million is the cut-off scientists believe increases the likelihood a man can conceive a child. Any lower number could indicate further fertility issues.
Furthermore, the men who were conceived naturally had an average of over double the amount of motile, or “swimming,” sperm, which makes it more likely sperm can reach and fertilize an egg.
Researchers do not believe that IVF causes fertility problems. Instead, they say the study discloses a link between the father’s fertility difficulties and those of the sons.