Not easy to script directly, as there is no SetGender command.
I verified that Leto doesn’t work in EE, either. On load, the .bic file is not used - the PC data is loaded from the player list in the file module.ifo within the .sav container. Leto appears to allow that to be changed, but it remains unaltered.
If you can identify the conditional script from the conversation, providing it is simply a check that the player is female, you can change it to
compile and put the .ncs file in override.
Alternatively, you should be able to use NWNExplorer to export module.ifo from the .sav, use GFFEditor to change the gender in the player list, then use NWHak to import the modified module.ifo to the .sav.
You may need to give the edited .sav a temporary name of less than 16 characters to work around NWHak restrictions, then rename to the original name.
As always, back up files before tweaking them!