Due to the more invasive nature of ICSI, there is a small risk of damage to eggs being injected(approximately 5%). Not all eggs collected will be mature enough or suitable for injection.
ICSI also carries a slight increase that chromosomal abnormalities could be passed onto ICSI children (about 2% above the rate that occurs in the natural population). It is also possible that male children of men with severe oligospermia may inherit this sub-fertility from their fathers.
Two-thirds of men who suffer infertility due to a congenital bilateral absence of the vas deferens (CBAVD), are also carriers of certain cystic fibrosis genes. For this reason, men inflicted by CBAVD, and their partners, may wish to undergo genetic testing before embarking on fertility treatment.