As a child, Zhang Shan was told she was born from her mother's armpit. It was an explanation she believed until she was 14.
Now 27, the Beijing woman is a little embarrassed by her naivety. 'But how was I supposed to know when nobody ever talked about this kind of thing to me?' she asked.
Many of Ms Zhang's peers received similarly creative replies about their birth - including being born out of a rock, picked out of a rubbish bin or found in a watermelon field.
'Most of us were left to find the truth about birth by ourselves during puberty or even later,' she said.
'In my case, a good friend told me what sex was when I was 19.'
China's twentysomethings are engaging in premarital sex and cohabitating at an unprecedented rate. But the nation's teens remain just as ignorant of sexual issues as previous generations.