Midwives have been told about the benefits of “close relative marriage” in training documents that minimise the risks to couples’ children.
The documents claim “85 to 90 per cent of cousin couples do not have affected children” and warn staff that “close relative marriage is often stigmatised in England”, adding claims that “the associated genetic risks have been exaggerated”.
We are talking of a huge difference between risks to a child by parents over 30 compared to a clear 15% risk with cousins having children. The actual risks are higher where there are recent (parent and grandparents) who were also more closely related.
It’s not a clear 15% risk. The actual risk to an individual child is in the 4-5% range, compared to 2.55% for the population as a whole.
Isn’t that likely compounded if children of first cousins end up reproducing with children from first cousins, and so on? As a one-off, those figures might be the case, but could well increase if the practice is endemic.