But this is not just about a lack of sex. More generally a lack of close intimate relationships is correlated with worse physical health, a lower sense of wellbeing, and worse mental health.
While sad, from the point of view of psychotherapy, this makes complete sense. The early foundation stones of intimacy are laid in those first interactions outside the womb. And if the bond between mother and baby is damaged or absent, then the life-long impact can be profound and ongoing. Like anything with human beings and mental health, it's not guaranteed and later relationships can allow people to make up the lost ground, but it is a very significant risk factor.
Which is why ripping babies off their mothers to protect them really should be an absolute matter of last resort - not a given - even if there is a history of abuse.
Yes, Oranga Tamariki do an incredibly hard job, with a heartbreaking array of children and families in awful situations, but how we respond to a mother and her new born baby needs to be informed by the importance of that early maternal bond - and support mothers, not blame them.
Because first do no harm. And while there may always be extreme situations where babies need to be removed from their mothers for their own safety, fracturing that bond can cause such deep and lasting harm that we run the risk of perpetrating - as a state and a society - the very harm and abuse we are seeking to end.