It would be a pity to retard our development by holding back those people who are gifted enough to work and play well with less than the average amount of sleep, if indeed it does them no harm.

Any accidental release of fluorine could also be an issue: fluorine is a toxic and corrosive gas and, at high concentrations, can retard plant growth and damage teeth and bones.

Others are spraying them with a chemical to retard growth.