It doesn't make you any less of startup material at all, it just puts you in a different environment. The original advice comes because when you're young and s

It doesn't make you any less of startup material at all, it just puts you in a different environment. The original advice comes because when you're young and single, you are without obligations, nothing to lose, able to take more risks, being naive (which can be good and bad), and being agile both location wise and time wise. Said that, if you do have a family, I think that has a set of it's own advantages such forcing you to manage time better, likely to go after ventures that are more likely to succeed, and having a family behind you for support.