In this study, we address the relationship between motility and genetic content of mouse sperm. The chromosome complements of highly motile mouse sperm, selected using the swim‐up technique, were analyzed after in vitro fertilization, at the first cleavage state. They were compared to those of unselected sperm. Identification of male and female chromosome sets was possible because of their differential condensation at the first mitotic division. In vitro fertilization, swim‐up separation, chromosome preparation, and staining were carried out using standard techniques. The results indicate that highly motile mouse sperm did not differ in types and frequencies of chromosomal abnormalities from those not selected for motility. Moreover, separation of motile sperm does not deviate the sex ratio from the theoretical 1:1. Copyright © 1990 Wiley‐Liss, Inc.
- Sex chromosome ratio