According to various surveys, men outnumber women in China by tens of millions more than three decades after the Communist Party instituted its infamous "one-child policy" following the 1976 death of Mao Zedong.
That's because, at least in part, parents have tended to want a male child, which created a phenomenon called "gender-selective abortion" in which a would-be mother would terminate her pregnancy as soon as the baby was determined to be female.
To protest the ongoing practice (which is technically illegal though still occurs), the Hong Kong and Shanghai offices of Grey Group collaborated on a project called "First Photo Last Photo," which refers to the fact that an unborn girl's ultrasound image which reveals gender can often be her last photo.