Failure of multitube sperm swim-up for sex preselection

Abstract

OBJECTIVE: To use double-label fluorescence in situ hybridization to evaluate a modified swim-up procedure that is purported to be effective for preconceptual sex selection. DESIGN: Controlled, blinded study. SETTING: University hospital laboratories. PATIENT(S): Donor males reporting for routine semen analysis. MAIN OUTCOME MEASURE(S): Percentages of X- and Y-bearing spermatozoa in neat semen and in two swim-up fractions, determined using double-label fluorescence in situ hybridization. RESULT(S): No clinically significant change from a 1:1 ratio was found in the distribution of X- or Y-bearing spermatozoa after double-label fluorescence in situ hybridization following a modified swim-up procedure and irrespective of the time (15, 30, 45, and 60 minutes) allowed for swim-up. CONCLUSION(S): Using fluorescence in situ hybridization, a modified swim-up procedure was evaluated for its purported ability to skew the relative percentages of X- and Y-bearing spermatozoa. No clinically significant change in the ratio of X- to Y-bearing spermatozoa was detected independent of time. Therefore, clinical application of this procedure should be strongly discouraged.