American educational researchers are surprisingly uninterested in this topic; I managed to find recent studies on it out of France, Italy (from last week!)[0], the UK, Sweden, Denmark, and the Czech Republic, but none out of the US. In fact, I found more material in the US about the gendered bias in grading by students of teachers than by teachers of students(!!!).

I'll look more into this to see if I can dig out an American specific study.

[0] https://www.tandfonline.com/doi/full/10.1080/01425692.2022.2...