It's true that the father's chromosomes determine the sex of the offspring.
But surely you're not prepared to argue that the FLDS men are XXXXY genetic oddities (extra X chromosomes sufficient to explain the skewed ratio of males to females).
Normal men are XY, meaning a roughly 50/50 ratio of offspring. Yes, male sperm are slightly less road-worthy compared to females, but only a percent or so.
Most male genetic oddities are XYY (extra Y chromosome) -- that argues for more male offspring, not less.
In any case, nothing other than murder or institutionalized murder or ostracism can account for the incredibly skewed ratio of males to females seen in the FLDS.
The simplest explanation is most often the correct one. The old men got rid of the competition for the young girls. Are we surprised?
...nothing other thanmurder orinstitutionalized murder or ostracism can account for the incredibly skewed ratio...