**Dr Spock was a real person.**

Quoting from [Wikipedia](https://en.wikipedia.org/wiki/Benjamin_Spock), 

>Benjamin Spock was an American pediatrician whose book *Baby and Child Care*, published in 1946, is one of the best-sellers of all time.

This Spock was in fact a doctor, and is usually referred to as "Dr Spock". Quoting (again) from [this discussion](https://groups.google.com/forum/#!topic/alt.startrek.vulcan/irTRKTNo2Ak):

> When Gene Roddenberry was informed that the name of his Vulcan was of a real
person it was too late to change it.  Star Trek and the baby-doctor both
emerged into the public eye about the same time and some people who knew little
of either confused the two into one.

This confusion has led to people - including some [famous people](http://www.dailymail.co.uk/news/article-2976068/She-just-mis-Spock-Kirstie-Alley-mocked-Star-Trek-fans-confusing-Leonard-Nimoy-s-character-namesake-child-psychologist-tribute-tweet.html) - calling Star-Trek Spock "Dr Spock" by mistake.