If modern science will ever come up with some trickery to measure a soul, it will more likely than anything else be tied to human sexuality. This, because orgasms are the most metaphysical state of human existence. Wilhelm Reich has at least tried to capture the magnificent, divine force generated by the human orgasm, which he named orgone, though his device was as crude as were the first human attempts in aviation.
Nevertheless, Wilhelm Reich's approach deserves the highest respect. Optimal human sexuality and orgasms generate a metaphysical form of energy which strongly reflects back on the organism that generates it. And while the force itself has so far eluded measurement, it's effects are easy to observe.
Not only is there a high temporary satisfaction. Optimal sex is simply the most effective life extension regimen, as it enhances the immune system and allocates a spirit to stay alive.