EFFECT OF SEXUAL ABSTINENCE ON THE PROPORTION OF X-BEARING SPERM AS ASSESSED BY MULTICOLOR FLUORESCENT IN-SITU HYBRIDIZATION

Objective: To document the relation between sexual abstinence and the proportion of X-bearing sperm in the ejaculate. Design: Prospective co hort study. Setting: Medical college. Patient(s): Ten normospermic men , aged 30 to 40 years, provided two semen samples: the first sample wa s 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 a lpha-satellite probes specific fur chromosomes 18, X, and Y were used to analyze 40,273 sperm. After 1.0 to 1.5 days of abstinence, there we re 47.6% +/- 1.7% (mean +/- SD) X-bearing sperm, and after 7 to 10 day s of abstinence, there were 49.6% +/- 2.1% X-bearing sperm. The X:Y ra tio increased marginally from 0.905 to 0.981. Conclusion(s): Sexual ab stinence 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 litt le impact on the secondary sex ratio. (C) 1997 by American Society for Reproductive Medicine.