Want to know who your ideal mate will be? Take a good hard look at yourself-- specifically at how tall you are.
Researchers at the University of Queensland compared DNA markers of more than 24,000 couples and found that they could predict the height of their spouses based only on their genes. People had actively chosen partners with genes for similar heights and (to some degree) weights.
This kind of selection has also been documented in nature. Brightly colored eastern bluebirds pair up, while the duller colored bluebirds tend to stick together. Larger Japanese Common Toads mate with each other, while the smaller ones do not. This boosts the odds that the traits will be passed onto offspring-- which is great if there’s an evolutionary advantage.
It’s like the old song goes: Birds do it, bees do it, even educated fleas do it, let’s do it- let’s fall in love with someone who’s about the same size and shape we are!