In the researcher's own words:
I ﬁnd that maternal athletic participation is an important determinant of infant health, as measured in the Vital Statistics Natality Files. The infants born to women who had access to greater athletic opportunities as teenagers are healthier at birth. High school athletic participation rates for girls increased from 5% in 1970 to 24% by the end of the decade, and I ﬁnd that an increase of this size results in a 6% decrease in low birthweight infants (<2500 grams) and an 8% decrease in the incidence of very low birthweight infants (<1500 grams). I ﬁnd little evidence that increased education or a change in observed behavior during pregnancy is the primary driver. At the same time, I do ﬁnd evidence that selection into motherhood is affected.When examined separately, the magnitudes of the estimated infant health effects are smaller for white women, but larger for black women. This difference likely reﬂects the fact that the black adolescents who participated in athletics as a result of Title IX are more disadvantaged, and have more to gain, than their white counterparts. In fact, the disparity in family background between black and white athletes is even larger than for non-athletes.