Really not sure I can 
Unless we already have a blog post on it (or it’s in my area of expertise) I can’t talk about stuff in the company 
I can say that it is rather bothersome and negatively affects Monzo in some ways (notice the hand wavey language I am using as to not give anything away) to not ask for gender at signup. But! We are happy to take that on to make our customer experience excellent 
There also appears to be some regulatory compliance we have to jump through to make this happen according to Rika:
And from Hugo:
TL;DR Customers come first at Monzo, always. Your experience matters. We will make money work for everyone and we are willing to jump through as many hoops as possible or take on the work to make it work for you.