Mormons have a flat tax that provides community welfare. Obviously, those with more resources can afford more children. If the welfare is distributed on moral grounds, as I suspect it is, as opposed to pure “need” (e.g. single mothers, adulteresses, addicts, criminals, etc.) then it would be all the more eugenic.

Traditional Christianity is highly eugenic as well, but this element has been eliminated by progressives, who demand Marxist forms of redistribution that fail to take moral behavior into account.

I live in a working class white region with lots of Mormons. Mormons are, by origin, working class whites. Their religion and social hierarchy are cleverly designed to improve the station and quality of working class people, and I’ve seen it work in real time. However, their unfortunate prohibitions and the science fiction origins of the religion are a bit of an impediment to conversion, to put it mildly.