Cause it gets more difficult to gamble when you have a child to support. You're more likely to look for a cushy job when it's not just your life at stake.
In my perspective, yes. A child has needs and there's a baseline cost in resources to supply those needs, not just material needs like food, clothing, shelter but more integible needs like time with their parent. As a parent you have responsibility to meet that baseline and should do so with as little risk as possible to provide stability for the child who is dependent on you and has no other options.
If you can meet all their needs, then whatever you have in excess certainly can be gambled if it can improve both of your odds, but only beyond that baseline threshold. That resource threshold for a parent is going to be higher than for a single person in the same situation, so you inherently have less resources to gamble than someone without a kid.
I would consider less resources as being less free to take unneeded risk, although it really just means you have less you can risk not that you have less ability to risk (unless of course you're already at or below that child's baseline needs where you're making sacrifices of your own needs for them). You could make further sacrifices on your own needs to gamble if that doesn't effect the child but chances are, it's going to effect both of you.
Theres an absolute magnitude of wealth/resources one needs to exceed before they start playing the capital gamble gamble, at least when your risk has significant effects on someone else, especially your own child.
