If evolution took its steady course and changed the genetic basis of height and age at first birth, we might not see women ten generations later who were shorter and matured earlier, for the effects of nutrition and culture could more than compensate for the genetic change. As a colleague of mine likes to put it, one good school-lunch program could be enough to obscure the biological effects.
即便进化的进程一直延续并最终改变了影响身高和头胎生育年龄的基因基础，但在10代人之后我们可能也无法看到更矮且更早发育成熟的妇女，因为营养和文化的因素可能会抵消甚至掩盖了基因的作用。