gehenna: My personal experience as a manager is my staff with children are the worst at going into overages with annual and sick leave, and don't make themselves available outside of business hours. My single staff are super dedicated and motivated to the point where I need to encourage them to use leave, and I know they can be counted on for the odd job outside business hours.
I will add I always remunerate or give time in lieu for that kind of outside hours work. I'm merely commenting on my differences of experience with @DaveB
What sort of work do you do? I'm in banking in a team of about 25 and two thirds have kids. Many, including myself, have had quite a bit of time off in the past year due to kids sickness, but thankfully we have a very supportive management team who say family first, then work.
Because of that attitude it's not uncommon to see a colleague who rushed off at 2pm for a sick kid working at 11pm or over the weekend making up the time. Our team is mature and we manage our own time and can work remotely.
Obviously not every workplace can operate like that but I'm grateful that my employer supports families.