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.

    106/222 (page 102)
    102 The Cause and Control of Sex ditions and occupational activities so absolutely unerr¬ ingly as to render wholly superfluous all other consid¬ erations. 171. Case 15. The father was of very dark com¬ plexion; he weighed from 175 to 190 pounds. The mother always weighed about 135 pounds and was prac¬ tically a blond. The family life began on the farm but the father was unsuccessful at this. He took up busi¬ ness pursuits. There followed in births, 4 Boys in succession 1 Girl 1 Boy 1 Girl 1 Boy. We have no exact occupational data as a basis for the segregation of these births, but the case is valuable as an example in weights and complexions. The father's excessive weight overcame his handicap in a weak com¬ plexion. Furthermore, the fact that he was not suc¬ cessful as a farmer appears to indicate that he was not very fond of the occupation and his dark complexion cor¬ roborates this view. It is probable too that prior to marriage the mother had followed outdoor habits ex¬ tensively, responding to the urge of her complexion. At any rate, the first four boys were born in response to the father's excess weight. When the family had grown to this size household duties were making in¬ creased demands upon the mother, resulting in her fur¬ ther seclusion within doors. To this is added the ori¬ ginal advantage of her light complexion and daughters finally became a possibility for her. 172. Case 16. In this case the father was a farmer. He and his wife were of about the same weight and both were in excellent health. The wife was very active; her work about the farm rivalled that of her husband. Without data as to complexions but with weights and exposure for the two being about equal, one sees a convincing regularity of alternations in the sex of their offspring: