What are the cons of NOT having kids?

Being a genetic terminal point.

All your ancestors watch as you extinct their line going into the future.

One description of life is reproduction. You didn't do that.

I know it was in style in your time, because of a stupid belief system revering nature and hating your species' success. You just self-deleted your genetic line by failing this IQ test. Biology is wonderful, a major aspect of evolution is subtraction. Thank you for helping with that math operation.