健康：环境污染 造成生男孩越来越难
The soaring number of gender-bending chemicals in the environment has disturbing fertility implications for humans and wildlife, scientists are warning. They say wild animals are being "feminised" by a host of common man-made pollutants which mimic the female sex hormone oestrogen and escape into seas, rivers, the earth and air when waste is disposed of.The chemicals--found in food packaging, cleaning products, plastics, sewage and paint--cause genital deformities, reduce sperm count and even turn males into females.
Dozens of species--including polar bears, fish, whales and otters--are suffering, according to the environmental group ChemTrust.
Fish have been badly hit by man-made gender-bending chemicals. In one study, half the male fish in British lowland rivers had signs of being feminised.
But all vertebrates--or creatures with backbones--have similar sex hormone receptors in their bodies. "Therefore, observations in one species may serve to highlight pollution issues of concern for other vertebrates, including humans," the report says.
Its author, Gywnne Lyons, a former government adviser on chemical-pollution, said: "Urgent action is needed to control gender-bending chemicals and more resources are needed for monitoring wildlife."
"If wildlife populations crash, it will be too late. Unless enough males contribute to the next generation there is a real threat to animal populations in the long term."
Some studies have shown that sperm counts in the West have fallen over the past 30 years. Others have shown a rise in boys born with genital deformities.
Communities heavily polluted with hormone-disrupting chemicals in Russia, Canada and Italy have produced twice as many girls as boys.
科学家警告说，环境中有越来越多可以改变性征的化学物，这对人类和野生动物的繁殖力产生了负面影响。
科学家说，由于一些产生雌性激素效应的人为污染物被处理时流失到大海、河流、土地以及空气中，因此，野生动物变得“雌性化”。
这些化学品可以在食物包装材料、清洗剂产品、塑料、污水和涂料中找到。他们可能会造成生殖器畸形、精子数量减少，甚至令雄性变成雌性。
据环保组织ChemTrust说，包括北极熊、鱼类、鲸鱼和水獭在内的数十种动物都受到了这种影响。
人为的改变性征的化学物对鱼类的影响特别大。一项研究显示，英国下游河流中一半左右的雄性鱼都有雌性化的迹象。
这项报告的作者格温·莱昂斯曾经担任政府在化学污染问题方面的顾问。她说，“我们需要采取紧急措施来控制这些改变性征的化学物。我们需要更多的资源来监测野生动物。”
“如果野生动物数目减少，那就会太晚了。除非有足够的雄性来繁衍新生代，否则长久以往，动物的数目将面临真正的威胁。”
其它一些研究显示，西方男性的精子数量在过去30年中有所下降。另外的调查显示，出生时生殖器畸形的男婴数目有所增加。
在俄罗斯、加拿大和意大利一些严重受到可以扰乱性征的化学物污染的地区，女婴的出生率要高过男婴一倍之多。
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