If the name is wrong as well (often it is when the gender is wrong, such as William when it should be Wilma), then I submit the alternative name, and in the explanatory text mention that the gender (and usually relationship, such as son instead of dau) are wrong. I also do this when the name is correct as far as it goes but can be expanded, such as George A. being commonly entered as an abbreviation for the female name George Ann.

If the name is full and correct but the gender is wrong anyway, then like frostfreedet, I just use the comment field on the record form. I also do this for other kinds of errors that do not allow user submitted corrections, such as relationships (a pretty common error is to see "in law" either omitted or spuriously inserted), or the parent names in birth and death records.

It unfortunately will not help with the indexing and thus the search functions, but at least it helps people who come across the record and might otherwise be misled by the incorrect info.