When you are thinking about how serious you want to get with someone, your body is making similar judgements with entirely different senses. Research has shown how smell helps determine attraction in ways that we can't be consciously aware of. Specifically, a new study shows that one of the ways we select partners is through evaluating their immune system through smells, so that potential offspring would have a good complement of immune genes.
And, like, they should have a nice smile.
Now scientists can synthesize these pheromones to trick our immune systems into thinking someone is a good match. Sort of like biological makeup. Actually, that's not new. Perfume already mimics natural scents (and often comes from natural places, like, no joke, regurgitated sperm whale prey). So, being able to synthesize these scents instead of fishing them out of the ocean is a good thing.
While these factors in attraction may seem totally arbitrary, keep in mind that attraction itself is fairly arbitrary, so whatever contributes to a "good fit," is not something to be ignored.