It happens nearly every day, every time he says name over the phone or exchanges business cards or pays for a bill with his credit card. First there is the pause, then the slight smirk or raised eyebrow and finally the stale joke. Something like, “Ha ha, you’re fired!”

Such is the life of Dr. Donald L. Trump, an oncologist and cancer institute executive of no relation to Donald J. Trump, the bombastic businessman and Republican presidential candidate.

Whenever Dr. Trump shows someone his passport or credit card, “eighty percent of the time someone will make a comment or will look at me, and you know what they’re thinking. I’m sure it’s that way with lots of other folks who share names with famous people,” he said.

“As you might imagine, it gives me a sense of what it’s like for really famous people dealing with the public, because invariably people will make some joke about my name,” Trump continued. “Like if I tell someone my name on the phone they will laugh or doubt my veracity, so you know it’s a famous name. Think about what all of the Michael Jordans in the country, must’ve put up with at the height of Michael Jordan’s visibility. But you know mostly it’s jokes, or asking for a loan, or asking who I fired lately.”