Why are Mexican American boys so much taller now?

Using NHANES data we find that the difference in average height between non-Hispanic White and Mexican American boys of ages 2-14 years has decreased 1.7 cm on average during the last quarter of the twentieth century in the United States. Our hypothesis is that the narrowing of the height gap is related to a larger gain in maternal height among Mexican Americans in relation to Whites. We estimate a child's height equation and find that on average about 38% of the reduction in the gap for boys of ages 2-5 years is attributed to this factor. The evidence of a secular trend for height is weak for the case of girls.