“操控”胎儿性别的科学方法

西班牙格拉纳达大学的一项新研究表明，女性的压力水平可能会决定胎儿的性别。

✔ 一项新研究表明在受孕前期中期和后期压力上升的女性生女孩的几率是其他人的两倍。

✔ 一个可能因素是带有X染色体的精子在女性精神状况不佳时更易与卵子结合。

✔ 另一个可能原因是孕妇精神压力大时，腹中的男性胎儿容易流产。

Stress in the modern world is generally viewed as a hindrance to a healthy life. Indeed, excess stress is associated with numerous problems, including cardiovascular disease, high blood pressure, insomnia, depression, obesity, and other conditions. While the physiological mechanisms associated with stress can be beneficial, as Kelly McGonigal points out in The Upside of Stress, the modern wellness industry is built on the foundation of stress relief.

现代社会往往认为压力阻碍了健康生活。的确，压力过大会带来许多问题，如：冠心病、高血压、失眠、抑郁症、肥胖和其他不良状况。尽管凯利·麦戈尼加尔在《压力的上升》书中所指出：有些与压力相关的生理机制是有益的，但现代健康产业是依然是建立在缓解压力的基础上的。

A new study, published in the Journal of Developmental Origins of Health and Disease, investigated a very specific aspect of stress on fetuses: does it affect sex? Their findings reveal that women with elevated stress are twice as likely to give birth to a girl.

一项发表在《健康与疾病发展起源杂志》上的新研究调查了压力对胎儿的影响的一个非常具体的方面：它影响（胎儿的）性别吗？该研究表明，压力增大后，孕妇生下女孩儿的概率增大两倍。

For this research, the University of Granada scientists recorded the stress levels of 108 women before, during, and after conception. By testing cortisol concentration in their hair and subjecting the women to a variety of psychological tests, the researchers discovered that stress indeed influences sex. Specifically, stress made women twice as likely to deliver a baby girl.

在这项研究中，来自格拉纳达大学的科学家们记录了108位女性在受孕前期中期后期的压力水平。研究人员通过测试她们头发中的皮质醇浓度，以及让她们接受各种心理测试，发现压力确实会影响孩子的性别。具体而言，压力会让女性生出女婴的可能性增加两倍。

The team points out that their research is consistent with other research that used saliva to show that stress resulted in a decreased likelihood of delivering a boy.

该团队指出，他们的研究与其他使用唾液作为测试指标的研究一致，都表明压力会导致分娩男孩的可能性降低。

Lead author María Isabel Peralta Ramírez, a researcher at the UGR's Department of Personality, Evaluation and Psychological Treatment, says that prior research focused on stress levels leading up to and after birth. She was interested in stress's impact leading up to conception. She says: "Specifically, our research group has shown in numerous publications how psychological stress in the mother generates a greater number of psychopathological symptomsduring pregnancy: postpartum depression, a greater likelihood of assisted delivery, an increase in the time taken for lactation to commence (lactogenesis), or inferior neurodevelopment of the baby six months after birth."

格拉纳达大学人格、评估和心理治疗系的研究员玛丽亚·伊莎贝尔·佩拉尔塔·拉米雷斯（María Isabel Peralta Ramírez）是这项研究的第一作者。她说，之前的研究集中在测量女性分娩前后的压力水平，而她则对受孕前的压力影响很感兴趣。她说：“具体来说，我们的研究小组在众多出版物中表明，母亲的心理压力是如何在怀孕期间转化成更多精神病症状的，例如产后抑郁，更有可能进行辅助分娩，延迟泌乳开始的时间，或者婴儿在出生六个月之后神经发育不良。”

第一作者：María Isabel Peralta Ramírez

While no conclusive evidence has been rendered, the research team believes that activation of the mother's endogenous stress system during conception sets the concentration of sex hormones that will be carried throughout development. As the team writes, "there is evidence that testosterone functions as a mechanism when determining the baby's sex, since the greater the prenatal stress levels, the higher the levels of female testosterone." Levels of paternal stress were not factored into this research.

尽管还没有确凿的证据，但研究小组认为，在怀孕期间母亲内源性应激系统的激活会决定整个发育过程中所携带的性激素的浓度。研究小组写到：“有证据表明，由于母亲产前心理压力越大，睾酮水平会越高，所以睾酮是决定胎儿性别的一种机制。”但父亲的压力水平并没有被纳入这项研究。

Previous studies show that sperm carrying an X chromosome are better equipped to reach the egg under adverse conditions than sperm carrying the Y chromosome. Y fetuses also mature slowly and are more likely to produce complications than X fetuses. Peralta also noted that there might be more aborted male fetuses during times of early maternal stress, which would favor more girls being born under such circumstances.

先前的研究表明，在女性精神状况不佳时，携带X染色体的精子比携带Y染色体的精子更容易与卵子接触。同时，男性胎儿成熟得比较缓慢，比女性胎儿更容易产生并发症。佩拉尔塔还指出，在母体早期经受压力的阶段，可能会有更多的男性胎儿流产，这将有利于在这种情况下出生更多的女孩。

In the future, Peralta and her team say an investigation into aborted fetuses should be undertaken. Right now, the research was limited to a small sample size that did not factor in a number of elements. Still, the team concludes, "the research presented here is pioneering to the extent that it links prenatal stress to the sex of newborns."

佩拉尔塔和她的团队表示，未来应该对流产胎儿进行调查。目前，这项研究仅限于小样本，许多因素未被考虑。尽管如此，研究小组总结说：“这项研究开创性地将产前压力与新生儿性别联系了起来。”