OK, so western women was a somewhat loose expression (the expression, not the women) which was intended to mean women in the US, UK, Europe... I could have said it better, but had I been arguing against me I doubt that I would have been arsed to up the ante over it. Women in the west are not a race, neither do they all share the same culture, so it's hard to know what else I could refer to them as. The point is that the trend for, er, these groups to have children later in life has increased, slightly, the risk of birth defects. For all I know that could be sperm, eggs or both contributing to that. I have no axe to grind. The statistic I quoted was that the slightly-increased risk of a birth defect arising from a birth to a 40-year-old is approximately the same as that from a one-off first-cousin union. Now that's the third time I've typed "one-off," and I did indicate that the risk increases in cases where serial first-cousin marriages occur. I did also point out the other, equally-important, elective risk factors. Saying all this is not in any way meant to be tendentious. I'm just saying it. Though, I repeat, I do wonder why it's come up in this context.