Children become curious about their sex organs by four years old, about where babies come from at five to eight, and conscious of sex differentiation at eight to twelve.
根據專家的研究，寶寶在四歲以前，對男女生殖器官會感到好奇。五歲到八歲，開始探問生命的起源。八至十二歲，認識性別角色。