Throwaway for anonymity, and yes, you read that title correctly.

A bit of backstory here: My younger brother is 16 years old, and has quite severe autism. We’re talking essentially a toddler in terms of independence, and is also completely non-verbal. And he has a foot fetish.

How do I know this? Because I have one myself. For those who don’t know, a foot fetish is something you’re born with (not unlike one’s sexual orientation), where the brain mistakes feet as a sexual body part, leading to the same (or higher) level of attraction to them as other actually sexual parts. As a kid, I remember having a distinctive but innocent interest in feet, which later turned into sexuality as I hit puberty. It seemed the exact thing happened with my brother – it started as an interest, however now that he is past puberty, it has grown.

As such, he frequently requests to see my mom’s bare feet, and when I say “see”, I mean touch, feel, sniff, and press against his face and body. To me, I see that this is the type of behaviour one with a foot fetish would do with an intimate partner, and can clearly see that my brother is getting sexually gratified by this. However, my family is blissfully unaware, brushing it off as just his autism, and “having an interest”, therefore letting him do it whenever he likes. I have seen him show desire towards other women’s feet too, so it’s not just my mom.

Remember how I said foot fetishism results in the brain treating feet sexually? Well as such, me seeing this type of behaviour is as disturbing to me as seeing them making out or engaging in other sexual activity would be. Whenever I see it, I resist the urge to scream out “INCEST”, and just leave the room.

This has to stop. On top of it being unbelievably inappropriate, I am deeply worried that this is essentially training him that it’s ok to just “take what you want” sexually, even if that is with a family member. But I really don’t want to have that conversation with my parents, because the only way they would believe that I am correct, is to have to go into my own fetishism with them, something only my girlfriend knows.

What should I do?