system
Given the following post, respond as if you're commenting on Reddit:
human
Did all people in medieval times have fetal alcohol syndrome to some extent?

In the last 50 years, science discovered that alcohol consumed by pregnant women, sometimes as little as one glass of wine, can alter the development of the brain and body of an embryo and lead to a fetal alcohol syndrome.
However, in medieval times in Europe, the water was so dirty that the people often had to drink (diluted) beer and other alcoholic beverages, including pregnant women in lack of better knowledge (and better water!). Even though the beer was much less potent than nowadays, i believe a constant consumption of alcohol must lead to the FAS, at least to some extent. However, I’ve found nothing about this topic.
So my question is: did a large portion of the population in this time have FAS? If so, how might the cognitive problems that come with this syndrome have influenced the society as a whole, when such a large portion of the population had it (this second question is purely speculative)?
gpt
...FAS has specific facial deformation that's detectable by skeletal remains. There are enough "medieval times" skeletons unearthed that show little FAS deformation to make "all people" a quantifiable "no".

But your question is problematic for other reasons.

Not everyone in "medieval times" drank alcohol instead of water. In European regions where the water supply and the sewer system was one and the same, it was SAFER to drink alcohol, yes. But alcohol wasn't consumed at the same rate or in the same quantities even to the same level as American alcohol consumption in the 18th and 19th centuries, and beer was nowhere near the 5% alcohol rate. Small beer, drunk by children, was usually less than 1-2% and most ales were 3-4% at best.

Medieval Western Europe was not North or South America, nor was it Africa, or Asia, or Australia. The Chinese boiled almost every drink they consumed, as did the Japanese. The countries and regions we think of as the Middle East had a much lower percentage of alcohol use than Western Europe, and North America had nearly none (while South American traditions of fermenting drinks were not everyday consumption).

So your question is ver Western European-centric in origin and excludes almost the entire world outside of Western Europe, without asking about the various cultures of non-Western European people (This includes pretty much everything east and south of Rome, and everything west of Ireland).

Hell, even European countries and cities had safe drinking water that were not London, because not all cities decided to turn their water supplies into open sewers.

And the answer is also relatively simple from an infant morbidity perspective. FAS babies tend to have weaker immune systems, worse overall health, and higher mental health / disabilities.

From the 12th century to the time of "modern medicine" in Western Europe, infant mortality was around 27% for the first year of life and then increased to nearly 65% by the age of six.

When 7 out of 10 kids die within the first six years of life, the likelihood that a FAS baby would make it to adulthood is super, SUPER low.

Please also note that the studies regarding alcohol use by pregnant women were done in America where a long traditional of teetotalerism and prohibition still infects a great many studies and government programs due in part to the fabled American inability to do self-destructive and short-sighted half-assed.

Those American-based studies are challenged semi-annually and almost always ignore imperical evidence from around the world, including very clear evidence from France, Germany, Ireland, the UK and other nations with a long tradition of drinking wine and beer, and the acceptable risk involved.

In short, limited and restricted alcohol consumption by pregnant women is as likely to cause FAS or other birth defects as walking outside in Houston on a hot day while pregnant.

And alcohol consumption by pregnant women during the Middle Ages was less of a concern than the mother surviving the pregnancy in the first place, not to mention the less than 1 in 5 chance the baby would make it to their own age of fertility.

So, combined with:

- Lack of historical and fossil record evidence of FAS bone deformation
- high infant mortality rate
- fact that other cultures without high alcohol consumption experienced the "middle ages" at the same time Western Europe did

I think it's safe to say that no, we are not all descendants of FAS kids.

Edit: FAS is not passed on genetically, and pregnant women were not generally the primary consumer of high potency alcohol in any given household in Western Europe anyway. Distilled alcohols didn't come into popular usage among the common classes until well into the 1600s, at which point we are out of "medieval times" and into the Renaissance Era of Western Europe. And since distilled alcohols are the primary vector for what we consider FAS defects, it's unlikely that it was as common as you suggest.

I mean, unless your geneology tracks back almost exclusively to a specific family that remained in a low safety zone for water quality for the past 40 generations and only intermarried with local clans and families while still consuming high amounts of alcohol throughout their lifetimes, you're not descended from FAS babies. You'd know. You'd look like the tail end of the Hapsburg family.