Somewhere, there is a City where all myths and legends mix and stand on street corners to wait for the bus. Where skyscrapers hold secrets and the sirens desperately attempt to tell the truth via local cable. Any story can meet another, even ones that are real.
On any given day, Sherlock might come out of the bathroom smelling like an Alpha on the hunt (Alpha #8) or an Omega in heat (Omega #9), a Beta brooding (Beta #3), or like no gender at all. The last one was his actual scent, which wasn't so much scentless as confusing. At least in an adult. If Sherlock and John were the sort of people to read Mills and Boon novels, they could have said that what occurred was because destiny intervened and set two destined lovers in their one true pairings' path. It was the lasagna.