Kim Tae Beom, Oh Jin Kyu, Kim Kwang Taek, Yoon Sang Jin, Kim Soo Woong
Department of Urology, Gachon University Gil Hospital, Incheon, Republic of Korea.
Department of Urology, Seoul National University Hospital, Seoul, Republic of Korea.
PLoS One. 2015 Nov 17;10(11):e0143054. doi: 10.1371/journal.pone.0143054. eCollection 2015.
In mammals, high parental testosterone levels present around the time of conception are thought to skew offspring sex ratio toward sons. The second to fourth digit ratio (digit ratio) is now widely accepted as a negative correlate of prenatal testosterone. Thus, we investigated the association between digit ratio and offspring sex ratio.
A total of 508 Korean patients (257 males and 251 females) less than 60 years old who had one or more offspring were prospectively enrolled. The lengths of the 2nd and 4th digits of the right hand were measured by a single investigator using a digital vernier calliper. Next, the patients' lifetime offspring birth sex ratios were investigated.
Maternal (rather than paternal) digit ratio was significantly associated with the number of sons (r = -0.153, p = 0.015), number of daughters (r = 0.130, p = 0.039), and offspring sex ratio (r = -0.171, p = 0.007). And, the maternal digit ratio was a significant factor for predicting offspring sex ratio (B = -1.620, p = 0.008) on multiple linear regression analysis. The female patients with a lower digit ratio (< 0.95) were found to have a higher offspring sex ratio (0.609 versus 0.521, p = 0.046) compared to those with a higher digit ratio (≥ 0.95). Furthermore, females in the low digit ratio group have a probability 1.138 greater of having sons than females in the high digit ratio group.
Maternal digit ratio was negatively associated with offspring sex ratio. Females with a lower digit ratio were more likely to have more male offspring compared to those with a higher digit ratio. Thus, our results suggest that the sex of offspring might be more influenced by maternal rather than paternal factors.
在哺乳动物中，受孕前后父母睾酮水平较高被认为会使后代性别比例偏向儿子。第二至第四指比例（指比）现已被广泛认为是产前睾酮的负相关指标。因此，我们研究了指比与后代性别比例之间的关联。
前瞻性纳入了508名年龄小于60岁且有一个或多个后代的韩国患者（257名男性和251名女性）。由一名研究人员使用数字游标卡尺测量右手第二和第四指的长度。接下来，调查患者一生的后代出生性别比例。
母亲（而非父亲）的指比与儿子数量（r = -0.153，p = 0.015）、女儿数量（r = 0.130，p = 0.039）和后代性别比例（r = -0.171，p = 0.007）显著相关。并且，在多元线性回归分析中，母亲指比是预测后代性别比例的重要因素（B = -1.620，p = 0.008）。发现指比低（< 0.95）的女性患者与指比高（≥ 0.95）的女性患者相比，后代性别比例更高（0.609对0.521，p = 0.046）。此外，低指比组的女性生儿子的概率比高指比组的女性大1.138倍。
母亲指比与后代性别比例呈负相关。与指比高的女性相比，指比低的女性更有可能生育更多男性后代。因此，我们的结果表明后代性别可能更多地受母亲而非父亲因素的影响。
