
You buy a kit from them, which they send to you, and then you spit in the tube they supply and return it to them. 6-8 weeks later you log in to their website and they have a complete gene analysis ready for you. This is what the kit looks like- nothing to be scared of!

This analysis can highlight medical conditions you may be a carrier for, diseases you may be prone to falling victim to, indicate what conditions your future children may be susceptible to, analyse your ancestry- all sorts of cool and interesting things.
Here's the link: https://www.23andme.com/