Yes, yes, we know. 

The very idea that you might ask a woman, in a manner you wouldn't a man, about her childbearing plans in a job interview. This coming to a certain prominence as Jacinda Ardern, the Kiwi woman about to lose a NZ election as Jezza did here, was asked what no one would ever dream of asking Mr. Corbyn.

A rising political star in New Zealand received a prominent new role — and was immediately asked whether or not she plans to have children.

Jacinda Ardern, who was appointed the leader of the Labour party on Tuesday, has less than two months before the next round of elections. She's the youngest New Zealand Labour leader ever, the BBC reports.

But enough about that. Multiple men wanted to know: What about her uterus?

Given our age, experience of this life and general wonkiness - even if personal experience might be in the slightest bit lacking - we're rather sure that more of the physique is involved than that. Still, there's a point that really does need to be made here:

Many viewers did not find the question so congenial. At the risk of stating the obvious, male politicians in their late 30s are not typically asked whether they're sacrificing their dreams of a family for their dream career.

The double standard is closely tied to misogynistic assumptions about parenting and ambition. And that's completely aside from questions of rudeness, or the fact that a person without children might be making a choice or struggling with infertility.

That's certainly one way to do it. Whether you think that's the best way is up to you:

"If you're the employer at a company, you need to know that type of thing from the women you're employing, because legally you have to give them maternity leave, so therefore the question is is it OK for a [prime minister] to take maternity leave while in office?"

For the record: In New Zealand (and the U.S.), it is illegal to discriminate against an employee because of current or planned pregnancies, and employers are advised to avoid asking that question altogether.

The basic lesson of economics is that there are no solutions, only trade offs. 

Start with that basic fact. We do indeed insist that - as we should perhaps - employers provide time off for those employees of theirs who give birth. In the UK system that employer must carry some (a small part, 10% last time we looked) of the wages paid during that period of maternity leave. They must also carry the disruption and costs of getting someone else to do that job for that time.

OK.

The price, that is the wages, on offer to someone who is known to be about to do that will be lower than to someone who is known to be not about to do that. No, do not demand that this should not be so, it is going to be so. Reality does not accord to your thoughts upon how the universe should be.

Now institute a system in which it is not permissible to ask about this.

OK.

What happens now? Anyone who might do this is now made that lower offer, perhaps tempered by the likelihood of it happening. Our ban on the asking has moved that lower value from those who actually have that lower value to all of those who might possibly have that lower value.

That is, the lower wages resultant from the costs of maternity leave are now applied to all women who might possibly take maternity leave. Or, as we might say if we look at it from the other way, there really is a gender pay gap for all women of likely child bearing age these days around 30 and above, up to the age of around the mid-40s. For never married women with no children at and past that age there is no gender pay gap, in fact there's usually a small, 1% or so, pay premium. For those who do have children there's a significant, about 9% per child, motherhood pay gap.

Why do women who have no desire for or are unable to have children suffering that gap? Because they're not allowed to point it out, employers are not allowed to take it into account.

Which is where that trade offs thing comes into play. If those who do not want children could say so, employers take account of it, then that mothers' pay gap would not apply to non-mothers. It is possible to imagine people signing off on an agreement to not take the maternity benefits if they change their mind.

No, we do not say that would be a better world. Nor that this one is either. We are simply insisting that they are different worlds and one precludes the other. A system which insists employers take no account, cannot do so, of child bearing desires is different from one where they can. The cost of having the world we do is the loss of the other.

It's useful to mull whether we've got the right deal here too. So, mull.....