To perform intracytoplasmic sperm injection (ICSI) in couples with primary infertility owing to sperm defects causing total immotility.Case report.Couple Sterility Center, University of Siena.Two infertile couples, the male members of which had "detached tail" genetic sperm defect.Physical and hormonal assays, semen analysis by light and electron microscopy, Y microdeletion screening, immunofluorescence, fluorescence in situ hybridization analysis of sperm nuclei, and PCR for partial sequences of AKAP4/AKAP3 binding regions were performed. The couples then underwent ICSI.Transmission electron microscopic analysis showed that the cause of sterility was "detached tail" genetic sperm defect. Immunofluorescence staining confirmed sperm structural alterations. Screening of Y microdeletions, partial sequences of AKAP4/AKAP3 binding regions, and fluorescence in situ hybridization did not show any sperm nucleus abnormalities. Three and two ICSI cycles were performed in the two couples. One pregnancy was achieved and a healthy baby with a normal female karyotype was born.One couple successfully underwent ICSI with "detached tail" sperm and gave birth to a healthy baby, suggesting that this structural abnormality may be bypassed by injecting sperm with a normal centriolar region.