['To assess the long Y chromosome genetic effect on human pregnancy outcomes.', 'We studied all records of pregnancies by human sperm donors after artificial insemination or in vitro fertilization at the Reproductive and Genetic Hospital of Citic-Xiangya. Fetal losses were compared from two groups of sperm donors: the observation group (with long Y chromosome) and the control group (without long Y chromosome).', '2885 pregnancies were achieved with donor sperm by artificial insemination and 1746 by in vitro fertilization. The rates of fetal loss, congenital malformation and donor fecundity in the observation group after both assisted reproductive technique were the same as for the control group.'] Is long Y chromosome a fetal loss risk?