Background: 近日，美国的科学家们表示他们发现了导致男士们脱发的原因并希望能早日找到治疗方法。研究表明人体内有缺陷的毛囊干细胞导致生长出来的毛发细得肉眼无法看得到。

For some men, bald is beautiful.

The iconic look may work for a few - especially celebrities - like the rugged Die Hard star Bruce Willis and Star Trek's Patrick Stewart.

An academic medical centre has found that hair follicles actually shrink, but don't disappear.

Dr George Cotsarelis, dermatology professor at Pennsylvania University, found the discovery hair-raising.

“What we found surprised us. The stem cells were present but they were not doing their job.”

The discovery of invisible hair sounds too good to be true. But what does it mean?

“It really gives us hope that because the stem cells are present itlowers the bar for developing treatments that could activate the stem cells and get them to form a new hair follicle,” said Dr Cotsarelis.

Treating these faulty stem cells means that, rather than just maintaining hair, we could soon regenerate hair.