Can you produce a specific quote from the section which you think covers it?

As far as I can tell, it isn't there. And methodologically the question is unaddressable. Their tool is measurement of family income. Without a way to address the value of housework, to them a family which has both parents working has more income and therefore is better off. There is simply no way to account for the value lost to the family because there isn't someone taking care of the home any more. That value is very literally outside the accounting system.

Now we all know from real life that having both parents work means that you have obvious large financial costs you would otherwise avoid. But putting a dollar value on that is far easier said than done.

Now they do talk about single parents skewing the disparity statistics. But they are just pointing out that single parent households tend to have lower income. In other words they are saying that by their measurement system, single parent families are worse. They aren't talking there about the extent of how what they are measureing does not match subjective reality for those households.

Cheers,
Ben