It is suggested here that Jongbloet has misinterpreted data on the variation of sex ratio with maternal age, social class, placental dysfunction, twinning and season. When all these matters are considered, it is not clear whether there is any truth in his supposition that male fetuses are generally conceived in suboptimal conditions. Finally, it is suggested that there is a circularity in his presentation of his concept of sex ratio 'reversal'.