Male and Female Families

In recent years, developments in the field of genetic studies have added depth to both genealogy and history. Genealogists can use DNA to trace relatives and to “prove” the ancestry that they have painstakingly eked out through paper trails. Historians can use genetic tests of current populations to prove or disprove theories of immigration or the disappearance of population groups.

Literature based on the renewed science of genetics is written for the public. Not only is the writing engaging but its theories can add new possibilities and interpretations to existing research and suggest new avenues to explore. A particularly accessible author is Bryan Sykes, a former professor of human genetics at Oxford University. In his book Adam's Curse he explores the reasons why it has been concluded that families have inherited tendencies to produce one sex more than the other. In some families this is more pronounced than others. Many of us have heard stories of the parents of boy after boy striving to have just one girl – all in vain.

                                         

Sykes puts the reason for families that are predominantly “male” or “female” down to the relative strength of the Y-chromosome or mitochondria. Interesting. Let's look at the family of Harold Strange Chambers and see if any pattern emerges to show if it is a “male” or “female” family.

 Chart of the Y-DNA of Harold Chambers family

This simplified chart of the Chambers family shows the male line from Harold's great-grandfather down to Harold and his brother. There were no females and two males in his grandfather's generation, then four boys in his father's generation, then the two boys of Harold's generation. This looks like a case of a predominantly male family until Harold and his wife produce one child, a daughter. Did the strength of the Y-chromosome peter out when it got to Harold or was the mt-DNA of his wife stronger? (No, her female line didn't just produce girls.) Clearly there are many forces at work when DNA is handed down from generation to generation. Who knows what science will reveal about DNA and heredity next?

Sources

Sykes, Bryan. Adam's Curse: A Future without Men,W.W Norton & Company Ltd., London, 2013.