日本的无脑儿：父亲年龄、母亲年龄及出生顺序

Ann Hum Genet. 1979 May;42(4):445-55. doi: 10.1111/j.1469-1809.1979.tb00678.x.

The statistical association between incidence of anencephaly and paternal age, maternal age and birth order was analysed in 1815 cases of foetal deaths with anencephaly reported during 1975--6. The birth order association was confirmed with an extremely high degree of statistical significance.

对1975 - 1976年期间报告的1815例无脑儿死胎病例，分析了无脑儿发病率与父亲年龄、母亲年龄和出生顺序之间的统计学关联。出生顺序关联得到了证实，具有极高的统计学显著性。