I don't see anything in the article about more morning sickness meaning higher IQ. It sounds like any vs. none, and the IQ spread is probably very small, anyway. Morning sickness is also protective of fetal health, so it just makes sense that it would be protective of IQ. I sincerely doubt that morning sickness causes a higher IQ. It seems far more likely that a lack of morning sickness can indicate a problem with fetal development, resulting in lower IQ scores.
FWIW, I was crazy nauseous but only threw up once.
