Records kept by European clergy reveal how in pre-industrial Europe there were cases of peasants keeping boy babies but killing girls, and today the custom of hanging a pair of trousers at the left side of the bed in the hope of conceiving sons still survives.
根據傳教士記載，歐洲農業社會時期，也有農民為生男孩而溺女嬰的例子，今天美國有些地區也還保有將長褲掛床左側的求男習俗。