Belva F, Bonduelle M, Buysse A, et al. - Researchers here examined if karyotype abnormalities in fetuses and children conceived by ICSI are associated with their father’s semen parameters. Karyotype results were reported from prenatal testing by means of chorionic villus sampling and amniocentesis and from postnatal blood sampling in offspring conceived by ICSI. From the 4,816 ongoing ICSI pregnancies, 4,267 pregnancies had information available on pregnancy outcome. In 22.3% of the pregnancies, prenatal testing was conducted, resulting in a diagnosis in 1,114 fetuses. They obtained a postnatal karyotype in 29.4% of the pregnancies in which no invasive prenatal diagnosis was undertaken, resulting in a total of 1391 neonates sampled. Twenty nine singletons and 12 multiples had an abnormal fetal karyotype (41/1,114): 36 anomalies were de novo, either numerical (n = 25), gender (n = 6) or structural (n = 5), and five were inherited. On combining pre- and postnatal data, they observed an increase in the odds of a de novo karyotype aberration with maternal age. Fetuses and children of couples with men having a sperm concentration < 15 million/ml, sperm concentration < 5 million/ml and total sperm count < 10 million, showed a higher rate of de novo chromosomal abnormalities. Analyses here suggest that in pre- and postnatal karyotypes of ICSI offspring, de novo chromosomal abnormality rate was higher than the general population and these abnormalities were related to fathers’ sperm parameters.