Swapping spit: what saliva can reveal about your romantic relationship

A simple spit test gives new meaning to 'having chemistry', as husband and wife analyze genetic material to find out whether couples are scientifically compatible

"I wanna know what love is," the song goes, and I think: yeah, me too. In 2015, 15% of Americans used an online dating service; if you are a butcher or baker or candlestick maker, there's an app for you. Our modern dating industry is built on the idea that you are too much of a dummy to find love yourself, and it is now worth $2.4bn.

The latest startup in this space is Instant Chemistry, a company built on the premise that your DNA could help you figure out who to love. Last month, I met co-founders Sara Seabrooke and her husband Ron Gonzalez at a nondescript laboratory in Toronto, surrounded by vials of spit.