Why do you mention DINK? Parent didn't say you should avoid having kids, even if you have a good dual income. He said you should not have more kids than you can

Why do you mention DINK? Parent didn't say you should avoid having kids, even if you have a good dual income. He said you should not have more kids than you can afford, taking into account child-induced career changes. That seems like a very reasonable statement. The net effect of that attitude is not that larger families break up. Larger families break up because they are trying to do something infeasible (i.e. trying to support more children than they can afford to support)