Hum Reprod. 2011 Jun;26(6):1551-4. Epub 2011 Apr 5. (搶鮮版)
我們記錄了10 847停經前婦女(平均出席年齡：37.5 ± 7.2歲，範圍 22-54歲）共生出21208活產出生嬰兒的性別，參加了我們的產科和婦科診所的評估。我們計算的新生兒性別比例相對於母親的月經初潮年齡（從 9到18歲），向每名婦女生育的嬰兒數（即生育指數）。
觀察母親誰進入初潮年齡在9歲;的比值比（OR）（95％置信區間）相比，有低後代的性別比例（男/女）的0.800(女多男少)，那些與對照組 14歲初潮為 0.72（0.29-1.79）。在性別比例仍然很低，直到該組的母親誰進入初潮在12歲 [1.009，OR：0.90（0.85-0.95）]。性別比最高(逐漸男多女少)，觀察母親與月經初潮年齡 14歲（1.118，OR：1.00控制），它逐漸下降，直至月經初潮年齡 17歲 [1.000; OR：0.89（0.15-5.26）](男女平衡)。婦女月經初潮年齡在9歲至11歲，生育率指數(胎數)也很低，。
Hum Reprod. 2011 Jun;26(6):1551-4. Epub 2011 Apr 5.
The sex ratio of offspring is associated with the mothers’ age at menarche.
M&K Health Institute, 30-9 Kariya, Ako, Hyogo 678-0239, Japan .
BACKGROUND Early menarcheal age is a risk factor for breast and ovarian cancers and is also associated with an increased spontaneous abortion rate. The aim of this study was to investigate whether there is a link between early menarcheal age and the offspring sex ratio. METHODS We recorded the sex of 21208 live born infants, all singletons, born to 10 847 premenopausal women (mean attending age: 37.5 ± 7.2 years, range 22-54) who attended our clinics for obstetrical and gynaecological assessment. We calculated the sex ratio of newborn infants in relation to the mothers’ age of menarche (from 9 to 18 years) and to the number of infants per woman (i.e. fertility index). RESULTS A low offspring sex ratio (males/females) of 0.800 was observed in mothers who entered menarche at the age of 9 years; the odds ratio (OR) (95% confidence intervals) compared with those of control group with menarche at age 14 was 0.72 (0.29-1.79). The sex ratio remained low, until the group of mothers who entered menarche at 12 years of age [1.009; OR: 0.90 (0.85-0.95)]. The highest sex ratio was observed in mothers with a menarcheal age of 14 years (1.118; OR: 1.00 control) and it gradually decreased until the menarcheal age of 17 years [1.000; OR: 0.89 (0.15-5.26)]. The fertility index was also low in women with menarche at the age of 9 to 11 years. CONCLUSIONS Women entering menarche outside the normal range, especially those with earlier menarche, may have an increased chance of producing female offspring.