Whoa... Dave, the light's hitting your bald spot just right. It's blinding me!

Very funny, as if you had an abundance of hair yourself. Actually I'm quite ok with my hair loss but I'd still like to know why it happens and if it's reversible.

We're not there yet but we may be closer. Japanese scientists recently discovered that when a gene called Sox21 is knocked out in mice, the rodents start losing hair two weeks after birth and are completely naked a week later.

Within a few days they regrew their hair but quickly lost it again.

This cycle continued for at least two years and affected both males and females. Turns out we humans also have the Sox21 gene. It's found in human scalp tissue and in the outer layer of the hair.

Each strand of hair is composed of three distinct layers each with different functions. The outermost layer is called the cuticle and it's a hard, shingle-like structure of over-lapping cells some 5 to12 deep.

What researchers found in mice is that those lacking the Sox21 gene did not have the normal interlocking between the inner layer of the hair cuticle and the outer layer.

That's what anchors the hair in the hair follicle.

These mice also made a lot less of the proteins involved in the scaffolding of cuticle cells that allows them to stick together which would affect the normal structure of the hair itself.

Though the study does not yet prove this gene is involved in human balding, it does further our knowledge of hair growth and retention and may help in developing treatments in the future.

As for this leading to a quick cure for baldness? I wouldn't hold my breath.