Not so much a bad employee IMO but definitely a worse fit for a company. I worked at a young startup (it was somewhat established by the time I joined) that was mostly younger guys than me (I was very early 30's they were mid 20's) and I was the only employee with kids. A lot of their focus and outside time was spent drinking hanging out and talking about work when they weren't partying. I couldn't and wouldn't do that and opened up a huge rift between me and management in particular. To be honest I think that is a problem with that company not with me as an employee. Their immaturity caused that and a metric shit ton of other issues. If any thing else I've found that having kids has made me better in a lot of ways. I'm more driven to build something to pass down, I'm more attached and caring about my career, and I'm more mature. I honestly believe that having children has made me a better person.