The historical choice has been the mother. 传统上都是把孩子交给母亲带，

Breast-feeding alone has made this both the logical and the biological choice. 仅仅喂奶这件事，就能从逻辑和生物的角度佐证这种分工，

But the advent of the modern-day breast pump has changed the equation. 好在抽乳器已经从某种程度上改变了这种情况。

At Google, I would lock my office door and pump during conference calls. 在谷歌的时候，我会锁上办公室的门，在电话会议期间抽乳。

People would ask, "What's that sound?" I would respond, "What sound?" 人们会问：“那是什么声音？”我会装糊涂：“什么声音？”

When they would insist that there was a loud beeping noise that they could hear on the phone, I would say, "Oh, there's a fire truck across the street." 当他们坚持说从电话里听到很响的“哔哔”声，我就会说：“哦，街上有消防车经过。”

I thought I was pretty clever until I realized that others on the call were sometimes in the same building and knew there was no fire truck. Busted. 我以为自己挺聪明的，直到我发现电话的另一方恰好和我在一栋楼里，人家明明知道我在撒谎。被逮个正着……

Despite modern methods that can minimize the impact of biological imperatives, women still do the vast majority of child care. 尽管现在有不少方法可以让女性在一定程度上摆脱生物学意义上的职责，但照顾孩子的一方大多仍是母亲。

As a result, becoming a parent decreases workforce participation for women but not men. 结果，升格为家长之后，女性的职场参与度明显降低。

Women who are the most likely to leave the workforce are concentrated at opposite ends of the earning scale, married to men who earn the least and the most. 最有可能离开职场的女性集中在家庭收入水平的两个极端，即其配偶处于收入水平的底层，或处于收入水平的高层。

In 2006, only 20 percent of mothers whose husband's earnings landed in the middle (between the twenty-fifth and seventy-fifth percentiles) were out of the labor force. 就美国而言，2006年，其配偶收入处于中等水平（即介于25%和75%之间）的婚育女性中只有20%退出职场。

In contrast, a whopping 52 percent of mothers with husbands in the bottom quarter and 40 percent of mothers with husbands in the top 5 percent were out of the labor force. 相比之下，其配偶收入处于底层水平的婚育女性中有52%退出，其配偶收入处于最高水平的5%的婚育女性中有40%退出。