VOA标准英语2011--Testosterone Drops When Men Become Fathe

Testosterone Drops When Men Become Fathers

Levels of the male sex hormone¹ drop sharply after men become fathers, a biological change that suggests men are hard-wired to care for their children, according to researchers studying human testosterone.
Previous studies have found that fathers have lower testosterone levels than non-fathers. Northwestern University biological anthropologist² Christopher Kuzawa says there are at least two possible explanations.
"Is it that fatherhood reduces your testosterone?" he asked. "Or do men with low testosterone to begin with, are they more likely to become fathers? And so what we did is, we followed men through time and measured their hormones³ before and after they became fathers."
Kuzawa and his colleagues tapped into a decades-long study of a group of men in the Philippines that measured participant testosterone levels in 2005 and in 2009.
During that time, some of the men were still childless, but others had become fathers.
"And those are the men where we see the largest decline in testosterone," says Kuzawa, who found that testosterone levels dropped by about half immediately after the birth of the child, then rebounded⁴ somewhat. Men who were actively⁵ involved in caring for their children produced less testosterone than men who were not involved.
It might be that men are programmed to have lower testosterone levels, so they can focus more on parenting than procreating. But Kuzawa says the hormone reduction carries with it some health benefits, too.
"Having high levels of testosterone can increase your risk for diseases like prostate cancer [and] testicular cancer. Also, testosterone can suppress the immune system so that you're less capable of fending⁶ off pathogens."
Kuzawa's study is published online in the Proceedings⁷ of the National Academy of Sciences.

1 hormone   

n.荷尔蒙，激素，内分泌

参考例句：

• Hormone implants are used as growth boosters.激素植入物被用作生长辅助剂。
• This hormone interacts closely with other hormones in the body.这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。

2 anthropologist   

n.人类学家，人类学者

参考例句：

• The lecturer is an anthropologist.这位讲师是人类学家。
• The anthropologist unearthed the skull of an ancient human at the site.人类学家在这个遗址挖掘出那块古人类的颅骨。

3 hormones   

n. 荷尔蒙，激素 名词hormone的复数形式

参考例句：

• This hormone interacts closely with other hormones in the body. 这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。
• The adrenals produce a large per cent of a man's sex hormones. 肾上腺分泌人体的大部分性激素。

4 rebounded   

弹回( rebound的过去式和过去分词 )； 反弹； 产生反作用； 未能奏效

参考例句：

• The ball rebounded from the goalpost and Owen headed it in. 球从门柱弹回，欧文头球将球攻进。
• The ball rebounded from his racket into the net. 球从他的球拍上弹回网中。

5 actively   

adv.积极地，勤奋地

参考例句：

• During this period all the students were actively participating.在这节课中所有的学生都积极参加。
• We are actively intervening to settle a quarrel.我们正在积极调解争执。

6 fending   

v.独立生活，照料自己( fend的现在分词 )；挡开，避开

参考例句：

• He is always spending his time fending with the neighbors. 他总是与邻里们吵架。 来自互联网
• Fifth, it is to build safeguarding system and enhance the competence in fending off the risk. 五是建立政策保障体系，提高防范和抵御风险的能力。 来自互联网

7 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼