There is no sensible explanation.  If you want a insensible one, do a search on beards. 

Maybe it's because Santa has a beard.

...because Russell sported a full beard and Rutherford needed to exorcise the ghosts (Russell) and establish himself as fully in charge of the organization. There is no biblical justification for clean-shaven men.

Politics.  JW men shave because of politics and history.

Gumby, you reminded me of a historical side-note from China:

Qing Dynasty

Although China's new rulers quickly learned Chinese culture and presented themselves as Confucian sages, they did impose one aspect of Manchu culture onto the entire Chinese male population. As a sign of submission to Manchu rule, the dynasty required all males to wear their hair in Manchu style. This style differed markedly from Chinese style and required shaving some hair at the top of the forehead and allowing the rest to grow into a long braided ponytail. In English, this hair style is commonly called the *queue.* It is easy to identify pictures and photographs from the Qing period because men will inevitably have queues during this dynasty but not before or after. Because wearing the queue was a political act, cutting it was one way to make an anti-Manchu political statement--a statement punishable by death during Qing times. (#graphic image#--very graphic; warning: not pleasant)

http://www3.la.psu.edu/textbooks/PM-China/ch10_main.htm

Let's hope the Watchtower never decides to behead men for not shaving.  Yikes what a thought.

I has to do with the fact that beards have pagan origins.

When we observe depictions of ancient Babylonian gods, many have beards. Those that were involved in pagan worship, offering children as sacrifices, erecting poles for sex worship and related offenses also wore beards. We have all seen numerous pictures in the publications that show these facts.

There is nothing in the Bible that indicates that Adam had a beard. As a perfect human, there was no need for one. But as sin spread throughout the earth, pagans adopted the desire for beards.

So, obviously, sincere Christians do not adopt practices connected with unpure worship.

***** Rub a Dub

I'm sure the society feels if the apostles or Jesus himself were alive in the Organisation today......they too would not wear a beard.

Gumby

....and yet the Society doesn't believe in evolution. Hmmmph.

They did'nt say anything about my Aunts beard at the meetings!!

so what's the dub explaination, anyone? I can remember something really wet at the time along the lines of (remember I lived in Plymouth, a naval town) people possibly mistaking dubs for naval people if they had beards

I thought that only applied to wearing clean underwear. I guess it only applies to men who have beards and long hair. Women can grow all the facial hair they want.