Advanced Parental Age and Wide Age Gap Effects on Human Secondary Sex Ratio in Romania

This paper aims to analyze the eff ects of parental age (especially advanced parental age) and age diff erence between parents on the probability of having a male/female off spring. The rationale of choosing this topic is based on the tendency of women to give birth at advanced age (>=35 years) and the increased frequency of couples with wide age gap. In order to conduct a successful research the data was obtained via survey, administrated online to the largest community of mothers in Romania. Using logistic regression models and statistical analysis we highlight the influence of maternal age, paternal age and the age gap on off spring gender. The paper brings new empirical evidence that advanced maternal age can shift the sex ratio in favor of male off spring and that a wide age gap between parents have influence on off spring's gender. The study is outstanding since the literature regarding the subject worldwide is conflicting and the one regarding Romania is very poor or nonexistent.