What's Wrong with Sex?

It seems to me that any sexual practice can lead only to dukkha due to sex's dependence on desire and fixation.  For example, sex is initiated by a desire for or fixation on an individual (or individuals for that matter) whom one finds attractive.  This desire and fixation is a means to fall into suffering because nothing inherently exists, and it would be rather silly to fixate on something that does not truly exist, now wouldn't it?  

However, without this kind of desire, it seems like it would be extremely difficult to, well, sustain or even begin any kind of sexual practice.  Furthermore, we humans are biologically programmed to desire and pursue and fixate on sex as a means to continue the species, making it difficult, if not impossible, to avoid.

So my question is:

Is it at all possible to engage in sexual activity without desire or fixation and therefore avoid dukkha?

Nicole Hohman