Effect of sexual abstinence on the proportion of X-bearing sperm as assessed by multicolor fluorescent in situ hybridization

Abstract

Objective: To document the relation between sexual abstinence and the proportion of X-bearing sperm in the ejaculate. Design: Prospective cohort study. Setting: Medical college. Patient(s): Ten normospermic men, aged 30 to 40 years, provided two semen samples: the first sample was obtained 1.0 to 1.5 days after ejaculation; the second, 7 to 10 days after ejaculation. Intervention(s): Abstinence. Main Outcome Measure(s): Proportion of X- and Y-bearing sperm in two ejaculates. Result(s): Multicolor fluorescent in situ hybridization using directly labeled α-satellite probes specific for chromosomes 18, X, and Y were used to analyze 40,273 sperm. After 1.0 to 1.5 days of abstinence, there were 47.6% ± 1.7% (mean ± SD) X-bearing sperm, and after 7 to 10 days of abstinence, there were 49.6% ± 2.1% X-bearing sperm. The X:Y ratio increased marginally from 0.905 to 0.981. Conclusion(s): Sexual abstinence marginally increases the proportion of X-bearing sperm in the ejaculate as assessed by multicolor fluorescent in situ hybridization. This change of borderline statistical significance probably has little impact on the secondary sex ratio.