United Nations statistics confirm that in the highly industrialized countries of Europe and North America, in the absence of extraneous factors such as war, the ratio of male to female births has generally maintained the natural balance.
在聯合國統計數字中，高度工業化的歐美，在沒有戰爭等外力干擾下，男、女嬰比例普遍維持自然平衡。