One study, yet to be replicated, looked at children whose mothers suffered from major nausea and vomiting during pregnancy. When the children reached school age, 21 percent scored 130 or more points on a standard IQ test, a level considered gifted. If their mothers had no morning sickness, only 7 percent of kids did that well. The researchers have a theory—still to be proved—about why. Two hormones that stimulate a woman to vomit may also act like neural fertilizer for the developing brain. The more vomiting, the more fertilizer; hence, the greater effect on IQ.
