The cause and control of sex in human offspring.

  • Jackson, R. Clay.
Date:
1926
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: The cause and control of sex in human offspring. Source: Wellcome Collection.

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    32 The Cause and Control of Sex drivers engaged in teaming. 1 asked one of them a few preliminary questions and then sought information as to whether he had a family and whether they were boys or girls. He replied, ''Yes, three girls. My astonish¬ ment can better be imagined by the reader than I can describe. I asked the next one about his children. He had two girls and one boy, and the third man had only one child, a girl. Also the form of my questions had brought answers which showed that this total of chil¬ dren had been born while the fathers were engaged in this outdoor occupation of teamster. I asked the two who had no sons if they did not think it about time to quit teaming and see if their luck with babies would not change. They looked mystified and probably won¬ dered more than once what I thought teaming had to do with babies. The data I had gathered thus showed that the chances on the first three cases were six to one in favor of the ''idea. The idea then rose promptly to the status of a respectable hypothesis with some very good reasons to substantiate it. 64. For some days I continued to take data in the case of teamsters and chauffeurs. Fifty-six cases may seem to be only a few compared to the scurrying army who daily drive Philadelphia's vehicles through her streets, but not every driver whom I saw afforded either excuse or fair opportunity for a conversation. Totalling the results in this number of cases, however, there were 203 children and the division showed 117 girls as against 86 boys. This was about 36% more girls than boys. Looking up the question as to the normal ratio of boys to girls in births for the whole population, I found that for the entire United States, out of 2053 births, 1000 are girls and 1053 are boys; 5.3% excess of boys. Therefore in my group of the families of teamsters and chauffeurs there was an actual excess of girls above nor¬ mal of about 40%. Note: In any case by dividing the total number of males born by the total number of femáis born we obtain a decimal. For example : 1053/1000=1.053. This result is termed the male sex ratio. To obtain the female sex ratio we reverse the division : 1000/1063=.947, female sex ratio. In the teamster group cited we have : 86 (males)/117 (females) =.785, male sex ratio.