Apparently, Bill Gates and Paul Allen (and Paul Gilbert) started a company before Microsoft, called Traf-O-Data. (wow.)

They did data analysis from traffic controllers.

Despite the name, they actually made a fairly decent revenue for high school kids (some tens of thousands annually). Once Bill's age was discovered they had a much harder time selling anything.

Even Steve Jobs had to stop being a shaggy hippie.

But luckily for founders, unless you're in the consulting business, the market really doesn't care who you are. There are far too many layers of abstraction for your identity to have any meaning, beyond of course, that which is deliberately constructed. (Mac People, Japanese Cars, German Engineering, Scandinavian design, etc) ^.^

Gates' father was a lawyer. It takes seed capital to found Traf-O-Data. Thankfully, the seed capital needed for a startup is dropping dramatically thanks to the web, but it's still a serious problem for people from poor families.

Gates' mother was richer than his father. And well connected, with a friend on the board at IBM. Though I doubt that mattered much...