I've been a bit late jumping on the income splitting bandwagon and with good reason - I thought I would wait until I could get my head around it.

It's probably no surprise to anyone who has watched me struggle to do basic mathematics that I still haven't got my head around it completely.

However, insofar as I can follow broad economic arguments, they seem to fall into two camps:

PRO: Encourages families to have one parent at home, which is usually considered a good thing for young children.

CON: Encourages families to have one parent, which disadvantages single people, and is a form of social engineering. Also, costs too much money.

Now, as you know I am someone who totally supports the childfree lifestyle and can think of nothing worse than endorsing breeding as the only way to live.

I personally like it - with some caveats, of course, like never sleeping through the night for more than three years - but I fully recognise it's not for everyone. And I would hate to think that single people are paying tax disproportionate to everyone else.

But here's what kills me about the argument that certain economists and commentators insist on having about this issue. Yes, having children is a personal choice and is perhaps little more than a narcissistic desire to achieve immortality through ensuring our genes live on after we do. But the fact of the matter is that once the children are here, it is best for everyone in society that those children are given the very best start in life possible.

Bringing up children is not like having dogs or luxury motorbikes - as worthy as those pursuits may be. It really is in a category of its own, for better or worse.

That doesn't mean either that only children with a parent at home are "brought up properly", but it has been shown to have generally positive side-effects for the child, and as a consequence, for the country.

Not forgetting the fact that many, many parents actually would like to - but can't - stay at home and look after their pre-school kids - and why the heck shouldn't that be affordable and encouraged, if only for those brief few years?

This nonsense about "social engineering" really boils my blood. Especially when it comes from the same people who are annoyed their tax dollars are going to single mums on the benefit, and would happily recount recent stories from the Herald suggesting some beneficiary families are actually living apart in order to claim two benefits, not one.

Help for families living apart? No way. Help for families living together? Err... forget it!

I was at a Plunket conference last year when the issue of income splitting came up, and it seemed to me a good idea. But when someone said it would cost the country $500 million in tax revenue, I reconsidered.

As a country we probably can't afford to lose this revenue right now, and in that regard it probably would be unfair.

Hopefully there will be a time of prosperity in New Zealand at some point in the future when we can afford $500 million to encourage parents to consider staying at home with their kids in those vital early years.

It is not misplaced "social engineering", or discrimination against single people, to wish it so.