Medina J R
J Hered. 1977 Jul-Aug;68(4):260-1. doi: 10.1093/oxfordjournals.jhered.a108828.
The influence on family size of the sex of the first children was studied in a sample of 1851 families of students in Sevilla University. Significantly more families limited family size to two or three children when the two or three children were of the same sex than in the opposite case. Significantly more families limited family size to three children when not all the three first children were females. The frequency of families having more than three children is not increased to a larger extent when the three first children are males than in the other cases.
在对塞维利亚大学学生的1851个家庭样本进行研究时，探讨了头胎孩子性别对家庭规模的影响。当两三个孩子性别相同时，比起孩子性别不同的情况，显著更多的家庭将家庭规模限制在两三个孩子。当并非头三个孩子都是女孩时，显著更多的家庭将家庭规模限制在三个孩子。当头三个孩子都是男孩时，家庭生育超过三个孩子的频率相较于其他情况，增加幅度并不大。
