I have an adopted child who is not exactly the brightest. Like 91 iq I think from state testing. Was a sweet child. We always assumed it was from bio mother

I have an adopted child who is not exactly the brightest. Like 91 iq I think from state testing. Was a sweet child. We always assumed it was from bio mother drug use. We have since met various bio grandparents, etc. Apparently reduced IQ just runs in the family.