My though on it, was that there is no doubt that start-ups depend on considerable time investments but even a person with a family can meet them. I personally work at least 60 hours a week and I have 4 kids. I also find plenty of time to spend with them. The difference is, if a employee cannot take some time during the day to deal with an issue because a start-up is in permanent crisis mode, then the start-up most likely has a process problem. There is really no reason that family concerns should inhibit the day to day activities of a start-up. There is also no reason that a start-up should be in a situation where employees are having to dedicate more than 60 hrs a week on a long term basis. If they are you have a bad start-up not a bad employee. People can't run at 70+ for several months on end, no matter there age.