综合一区欧美国产,99国产麻豆免费精品,九九精品黄色录像,亚洲激情青青草,久久亚洲熟妇熟,中文字幕av在线播放,国产一区二区卡,九九久久国产精品,久久精品视频免费

Boys today may be hitting puberty earlier

(Agencies)
Updated: 2010-12-07 11:29
Large Medium Small

Boys today may be on a faster track to puberty than their fathers' generation, reaching the milestone an average of a year earlier, according to a study conducted in Bulgaria.

The findings suggest that trends toward earlier puberty aren't limited to girls, who have already been shown to be developing sexually at increasingly younger ages.

In the study, reported in the Archives of Pediatrics and Adolescent Medicine, researchers from Cedars Sinai Medical Center in Los Angeles compared 6,200 healthy Bulgarian boys with a similar 1970s study. Both measured height, weight, testicular volume, penis length and circumference.

"Studies done several decades ago in the same population reported that a leap forward in sexual development occurs at ages 13 through 16," said Fnu Deepinder, who led the study, in an email to Reuters Health.

"However, our study indicated that this spurt takes place between 12 and 15 years old."

Deepinder and his colleagues found that boys' testicles did not grow substantially until the beginning of puberty, around age 11. But penises appeared to grow gradually from birth to sexual maturity, starting at around 5 cm (2 inches) and reaching an average length of nearly 9.5 centimeters (4 inches) by the age of 19.

However, both penises and testicles grew most rapidly between ages 12 to 16, while boys added the most inches in height and gained the most weight between 12 and 14 years gold.

The study also found that while boys of the same age in the 1970s study had relatively smaller genitalia, men are not necessarily more well-endowed today, with size differences disappearing by age 17.

Boys in rural areas had slightly longer penises than their urban peers, although the difference was only about 0.4 cm (0.2 inches).

Deepinder said that genetic, environmental, nutritional and educational factors could all be behind the faster development today, but it remains unclear what impact earlier puberty might have on men's health.

It also remains unclear whether specific differences exist between populations from different parts of the world.

阿瓦提县| 探索| 翼城县| 邵武市| 潞城市| 涪陵区| 上高县| 博乐市| 来凤县| 榆林市| 武强县| 琼结县| 长汀县| 襄樊市| 嘉黎县| 平江县| 东台市| 辰溪县| 那坡县| 长沙市| 怀安县| 托里县| 新蔡县| 临江市| 探索| 巴南区| 江孜县| 安阳县| 武威市| 西宁市| 友谊县| 广德县| 吉水县| 祁连县| 通山县| 铁力市| 万年县| 腾冲县| 秭归县| 哈巴河县| 迁安市|