It's well known there are proxies are you can't use when building a credit risk model e.g. zip codes are off limits because it can be used to a proxy for ethnic

It's well known there are proxies are you can't use when building a credit risk model e.g. zip codes are off limits because it can be used to a proxy for ethnicity. Intentional or not, it's possible they could have used something that proxied for gender.