The observations of many years enabled determination of maternal factors which influence the sex of progeny. Factors on side of the father have long been neglected, even though the sex of progeny depends on the sex chromosome in fertilizing spermatozoon. The data obtained by penetration method 'hamster oocyte - human sperm' show differences in the proportion of sperm cells, depending on the method of capacitation used. On this basis the hypothesis has been formulated that the factor which precludes the proportion of sex at fertilization may be different time of capacitation of sperm cells. The cause of the phenomenon remains unclear.
Copyright 2001 Harcourt Publishers Ltd.