There are so many reasons to hate the idea of ‘mental age’. First, there’s the obvious one: talking about mental age often results in people treating adults with intellectual and developmental disabilities like children. If you’re 50 and have an ID or DD, you’re still 50.

You still have 50 years of life experience from which you can draw.

I also hate mental age because unscrupulous adults use it to claim that children and teens have a higher mental age than their physical age and use it to groom them.

Focusing on mental age rather than life experience results in exploitative practices. Kids aren’t allowed to be kids and adults aren’t allowed to be adults.

And teenagers aren’t allowed to become healthy adults, either because they’re still being infantilised or are being forced to grow up too fast.

I would recommend talking to/following @lauralovesian1, who’s talked extensively about mental age and prejudice against people with intellectual disabilities.

[CW child sexual abuse]

Mental age theory results in arguments like ‘She’s a 12-year-old with a mental age of 18, so it’s totally OK for her to have sex with a 25-year-old!’ Or ‘He’s 45 but has a mental age of 8, so let’s put him in an institution.’

Mental age should be scrapped because it enables abusers and interferes with the social, emotional, and intellectual development of people with IDD.