In evolutionary terms, this correlation may make sense.
从进化论角度看，这种说法也是有道理的。
Males' breeding potential is strongly influenced by fitness, while females breed more consistently.
男性的生育能力受健康状况的影响较大，而女性的生育能力则更为稳定。
"If a mother has plentiful resources then it can make sense to invest in producing a son because he is likely to produce more grandchildren than would a daughter. However, in leaner times having a daughter is a safer bet," Mathews said.
马修说：“由于男孩能够‘传宗接代’，所以在生活富足的情况下，女性为了生男孩而不惜大量投入确实可行，但在物质匮乏时期，还是生女儿更保险。”
Some researchers have been sounding alarms for years over the change in sex ratios in developed countries and have in the past blamed pollutants and synthetic chemicals such as those found in some pesticides which disrupt human hormones.
近年来，一些研究人员一直在就发达国家的性别比率问题发出警告，并将这一问题归咎于各种污染物以及一些杀虫剂中所含的化学合成物，这些物质会损害人类的荷尔蒙。
The latest findings were published in the journal Proceedings of the Royal Society B: Biological Sciences.
这项最新研究结果在《英国皇家学会会报B：生物科学》上发表。
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