"If you want to figure out somebody's age, ask what finger they use to ring the doorbell. If it's the index finger, chances are, they're over thirty.
The thumb is becoming the choice of teens and the twenty-something crowd, who seem to prefer texting over talking - and that's triggering a wave of health warnings and predictions.
Blackberry thumbs, twitter tendonitis - if the headlines hold true, the thumb texting generation may be facing a future of hi-tech hurt.
"It's too early to tell, there's not a true diagnosis of 'blackberry thumb,'" said Tamara James, Duke University ergonomics expert.
James says scientists are just starting to study the physical impact of texting.
"Well the thumb is definitely emerging as the high tech digit," said James.
And early evidence suggests that thumbs are getting bigger.
"They do have really strong thumbs - from what I understand and from what the research has shown," said James.
Only time will tell if those stronger thumbs are better suited for the rigors of texting.
Researchers are also investigating back, neck and complaints, as well as addiction.
"And you may have heard the term 'crackberry' used," said James.
Technology is taking the fall for what is really a human behavior problem.
"They just can't put it down," said James. "They are constantly using those thumbs, constantly texting." (Continued via Children's Health Link) [Ergonomics Resources]