This 2017 German human study explored the relationship between birth stress and handedness. The authors summarized previous research which, among other points, estimated epigenetic contributions to handedness as great as 75%.
The research hypothesis itself was worthwhile based on the prior studies cited and elsewhere such as Is what’s true for a population what’s true for an individual?. But the study hit a snag in its reliance on the sixty participants (average age 24) completing, with the assistance of their parents and medical records, a 24-item questionnaire of maternal health problems during pregnancy, substance use during pregnancy, and birth complications.
The subjects didn’t provide accurate information. For example:
- Only one of the subjects reported maternal alcohol use during pregnancy. An expected number would have been twenty-six!
- None of the subjects reported maternal mental illness during pregnancy. An expected number would have been at least seven!
The subjects’ parents willingly misled their children about facts of their child’s important earliest development periods. Their lies and omissions were not only unethical to the children, but also, whenever they became recognized, diminished or destroyed the society among family members.
As mentioned on the Welcome page, lies and omissions ruin the standard scientific methodology of surveying parents and caregivers. The absence of evidence greatly increased the difficulty for researchers to determine causes of epigenetic effects still present in the subjects’ lives.
The parental lying was again unethical in that it diminished or destroyed the society between the sources of information – the research subjects – and the users of the information. It adversely affected anyone who valued evidence-based research.
http://www.tandfonline.com/doi/full/10.1080/1357650X.2017.1377726 “DNA methylation in candidate genes for handedness predicts handedness direction” (not freely available)