I have a within subjects survey data. One variable is gender where I check if there is a gender difference in body perception. For this I understand that I have to use weights but the rest of the analysis doesn't use categorical variable other than the levels.

The question is, if I want to check if there is a difference between body perception with or without tattoos and separately its interaction with gender, do I have to use weights by gender prior to any analysis or only in case of the interaction with gender?

I can specify my question, if it's not clear enough.

Thank you