Sexing of human sperm by discontinuous Percoll density gradient and its clinical application.

A discontinuous Percoll density gradient was employed for the selective isolation of human X-bearing sperm. The fraction rich in X-bearing sperm that sedimented through eight steps of a Percoll density gradient was inseminated into healthy volunteers. Six couples achieved pregnancy and each delivered a female baby without abnormality. For further separation, a Percoll density gradient consisting of 12 steps gave a 94% purification of X-bearing sperm (contamination with Y-bearing sperm: 6.4 +/- 1.8%) with a mean recovery of 23.3 +/- 6.4% (n = 6).