Never on that matter. They're more concerned about his emotional maturity - unfortunately, my parents didn't bothered to talk me out of my ex-husband because they felt they shouldn't interfere with my relationship choices. I was 21 and knew nothing about relationships (thank you, teenage boys, for making sure I never found out), so it never crossed my mind that a man ten years older than me could be less emotionally mature than I was.
I learned it the hard way. Age really does not matter - it's his emotional maturity that makes all the difference in the world.