At Last! an Answer to the Question: Where Does Belly Button Lint Come From?

"Revealed: The secrets of belly button fluff "
Telegraph.co.uk (March 1, 2009)

"In what must be the ultimate exercise in navel-gazing, an Austrian scientist has solved the mystery of belly button fluff.

"After three years of research, Georg Steinhauser, a chemist, has discovered a type of body hair that traps stray pieces of lint and draws them into the navel.

"Dr Steinhauser made his discovery after studying 503 pieces of fluff from his own belly button...."

Okay: This isn't the most relevantly, socially-conscious, likely-to-win-a-Nobel-Prize bit of research to come down the pike recently. But, I was interested in how lint finds its way into my belly button: and why it doesn't happen so much with my wife.

More:

"The nature of navel fluff "
ScienceDirect (December 31, 2008; 13 January 13, 2009; February 23, 2009: received, accepted, available online, respectively)

"Hard facts on a soft matter! In their popular scientific book (Leyner M, Goldberg B. Why do men have nipples – hundreds of questions you’d only ask a doctor after your third martini. New York: Three Rivers Press; 2005), Leyner and Goldberg raised the question why 'some belly buttons collect so much lint'. They were, however, not able to come up with a satisfactory answer. The hypothesis presented herein says that abdominal hair is mainly responsible for the accumulation of navel lint, which, therefore, this is a typically male phenomenon. The abdominal hair collects fibers from cotton shirts and directs them...."

"Scientist Solves Mystery of Belly-Button Lint"
FOXNews (March 3, 2009)

"One of life's greatest mysteries has now been solved.

"Georg Steinhauser, a young, affable Austrian chemist, spent three years gazing at his own navel — and those of friends and family as well — to discover how exactly we get belly-button lint...."