What you say about the Maori is very interesting. There were other ancient cultures, however, that held a very different point of view. The Taiosts, for instance, regarded love-making as an opportunity for healing, as well as procreation and pleasure. Kissing was an essential component and the exchange of various body fluids (though not all) was considered very therapeutic.
Personally, I do believe that there are 'laws of nature', but I consider them to be far more basic and stable than the fluctuating influences of any particular culture or conditioning.