The ratio of X- and Y-bearing sperm in ejaculates of men with three or more children of the same sex.
OBJECTIVE
The present study evaluated the proportions of X-bearing and Y-bearing sperm within the semen of donors who were the declared fathers of three or more sons or daughters.


METHODS
The proportions of sperm were determined using dual-color fluorescence in situ hybridization to identify the X and Y chromosomes.


RESULTS
The only difference observed was in semen volume. There was no increase in the proportion of Y-bearing sperm for men with only sons (49.7 +/- 1.3%) or of X-bearing sperm for men with only daughters (44.8 +/- 2.6%).


CONCLUSIONS
A preponderance of either sons or daughters in a family cannot be explained simply by an altered ratio of X-bearing and Y-bearing sperm in the father's semen.
Irving
J
J
Centre for Human Genetics, Edith Cowan University, Joondalup, Western Australia.
Bittles
A
A
Peverall
J
J
Murch
A
A
Matson
P
P
D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D012661:Semen / Q000166:cytology*; D019849:Sex Determination Processes; D017678:Sex Distribution; D013094:Spermatozoa / Q000648:ultrastructure*; D014960:X Chromosome; D014998:Y Chromosome