Cleavage rates from the Colorado study did not differ
between nonsorted and X-sorted sperm, but the sperm
concentration was four times higher during IVF for the
X-sorted sperm. For the Florida study, identical sperm
concentrations were used for X-sorted and nonsorted
sperm, and fertilization time was shorter than in Colorado.
Probably as a result, cleavage rates were lower for sexed
sperm.