As a guy who has worked 13 hour days while having a kid when it was required (as well as 2 night binges on the weekends prior to a Monday launch), I do get sick of the "less likely to work late when its needed" stigma against married people. I'll work late when its needed, in bursts. What I won't do is work 80 hours a week for 3 months so my boss can continue on with the delusion that I'm being as productive as 2 people working 40. We all know that's bullshit, and science says so.

Its funny, because the 20 something single guys I work with (anecdotal of course) don't seem to be willing to sacrifice personal time. They'll work late on a Tuesday, but getting them to work late on a Friday or come in on a Saturday? Not happening.