The purpose of this study was to retrospectively compare the overall results and embryo quality in 102 cycles of in-vitro fertilization (IVF)-embryo transfer using normal frozen donor semen (group D) and 94 cycles of IVF-embryo transfer using husbands' teratozoospermic sperm (group T). Donor semen was purchased from men with proven fertility and normal semen parameters. Teratozoospermia was defined in group T as the presence of 20 x 10(6)/ml), there was no difference between them with regard to fertilization rate, pregnancy rate or embryo quality. This study confirms low pregnancy rate per cycle in IVF-embryo transfer using teratozoospermic semen, but demonstrates for the first time that embryo quality and viability are not impaired. It is proposed that the poor pregnancy rate per cycle obtained is due only to the poor fertilization rate, and to the subsequent limited choice of embryos to be transferred.