That decline of the nuclear family allows us to solve the gender pay gap

We're not sure that Sir James Munby has things quite right here:

Britain should "welcome and applaud" the collapse of the nuclear family, the most senior family judge in England and Wales has said. 

In a speech Sir James Munby, the president of the High Court's family division, said the modern British family was "complex" and "takes an almost infinite variety of forms". 

He said that "whether through choice or circumstance", many people "live in families more or less removed from what, until comparatively recently, would have been recognised as the typical nuclear family. 

The nuclear family is still, after all, the modal arrangement. Not something we expect to change all that much in a species descended from a millennia or two (to look only at English household arrangements and to be strict about the meaning of "nuclear") to hundreds of millennia (with a wider definition of nuclear to mean extended familial grouping) of such families. That being rather the way evolution works, there's a tendency for us to be doing things because we're descended from people who did those things. It's when the environment changes that they become non-optimal strategies.

We're also liberals and thus hugely applaud the increase in the ability of people to live their lives as they themselves wish. However, the specific point of interest here is this:

The most recent figures from the Office for National Statistics show that there are around 10,000 same-sex couples in the UK who have dependent children. 

There are, roughly speaking, two competing theories about the gender pay gap. It's all about misogyny, capitalism perhaps, the oppressions of The Man. Or, it's just about primary childcarers and that just tends to be women. That rise in the number of same sex parents gives us a population allowing us to tease out the two effects. We could, perhaps, look at the incomes of the primary childcarer in such relationships as opposed to the other. Or see whether male primary childcarers see the same income limitations as female - something we could also look at through the rising number of cis- and hetero- male primary child carers.

We're pretty sure what would be revealed - we'll see the same career structures and income changes among primary childcarers regardless of sex, gender or that of partner. But even if it turns out the other way around, that it is actually The Man causing it all, we'd like to see the research done.

Because it would be useful to be actually able to identify, properly and fully, the cause of the perceived problem, wouldn't it? For only when we've done that can we possibly try and craft any solution to it - or even decide whether it's something that it's worth trying to solve.