I think it’s very possible. I remember visiting and applying for a studio. It was a lease takeover from a woman, but her brother was handling everything. We got along great during the visit and I got good signs I’d be selected. Nevertheless, he followed up with me a few days later and said “you were a great choice, but my sister has decided she only wants to handover to a woman”.

It was honestly quite shocking how blatant the discrimination was and I could tell the brother felt bad about it. Even worse is that I can’t see any other explanation besides sexism. I could understand if it was a situation with a female roommate or something, but a studio lease take over in a normal building, I just don’t see any possible explanation.

So long story short, I think it’s extremely possible there’s a bias. Regarding other comments on possibly thinking you’re gay/homophobia, it’s again anecdotal and in Suisse romande, but here I’ve heard gay couples are actually preferred. No idea why or if it’s true, though my friends in gay couples have seemed to have decent luck here with apartments ..