Wood elves are reclusive and tribal. They avoid human culture in general, although there are outliers from time to time.
Due to interactions with humans and other races, there are plenty of half-elves in the major city states.
Drow are essentially a genetic anomaly. Elven parents can occasionally (1 in 50 roughly) give birth to a dark skinned elf who develops drow characteristics in adulthood. There isn’t a cure for this, nor any genetic predictors – it happens to both high elves and wood elves, and two drow parents are no more or less likely to give birth to a drow child.