The sex ratio of offspring of pilots of high performance military aircraft
Snyder, R.G.
Human Biology 33(1): 1-10
1961
ISSN/ISBN: 0018-7143 DOI: 10.2307/41448473Document Number: 472680
Data were obtained on 236 married pilots representing the total fighter pilot population at three different military airbases. One hundred and eleven of these individuals fathered 222 children, 113 males and 109 females. The date of birth for each child formed a basis for the assumed date of conception for each offspring and the flight records for each father were examined for the period from 3-0 months prior to assumed conception. It was found that there was a statistically significant preponderance of female offspring born when fathers flew fighter type aircraft prior to conception .01> p > .001. Of 94 children conceived and born under such conditions, 59 were females, while only 35 were males. This results in a sex ratio of only 59.3, compared to an expected ratio of 105.37. It was also found that the relationship of parity (birth order) to the sex ratio agreed with the expected when the fathers flew transport types of aircraft or did not fly prior to conception, but that a significant reversal of this relationship occurred when father flew fighters prior to conception of each child. This study gives statistical support to the hypothesis that the secondary sex ratio is significantly altered toward a preponderance of female offspring when the fathers have participated in high stress fighter-type flying prior to conception.