First Name = Last Name?

I worked in an office with a girl who had the last name "Handler" (by marriage). I also heard the office refer to her spouse as "Handler, Handler." I eventually figured out his first name was no different from his last name. That's the only person I know personally with that characteristic, but I guess he is not alone:

https://www.whitepages.com/blog/how-many-americans-have-almost-the-same-first-last-name/