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In addition to the exhaustive commentary by Prof. Brown , the following might be noted. “Advanced paternal age” may be indeed “associated with negative effects on both mothers and offspring” . However, Khandwala and colleagues  do not discuss the social implication of this statement as the dilemma in a developed country (including Russia) can sometimes be an older compatriot or a younger immigrant as a potential father. The advancing gender imbalance is a known fact; its main cause in some developing and newly industrialized countries is sex-selective abortions  but in more developed countries with relatively low birth rates the main cause of gender imbalance is immigration as immigrants seem to be predominantly young males.
In any case the results of  should be verified by animal experiments. Animal data are only scarcely discussed in .
1. Brown HK. Paternal factors in preconception care: the case of paternal age. BMJ 2018;363:k4466
2. Khandwala YS, et al. Association of paternal age with perinatal outcomes between 2007 and 2016 in the United States: population based cohort study BMJ 2018;363:k4372.
3. Jargin SV. The male to female ratio at birth: The role of femicide and other mechanisms. Early Hum Dev. 2018;123:33-34.