I've been playing with a self created race. Everything works pretty well except for the fact that some npc's use "madame" to address my male character.

I first noticed this when I talked to Arrille with his disposition being at 90. I went and checked through his dialogue, and the condition for him calling a character madame is samesex=1, which shouldn't have caused a problem.

Can anybody enlighten me to what the source of the problem could be?

This is not a problem specific to your race, or user-created races in general -- besides that, the reason for the problem has been right in front of you all along:

Well it's because I also asked the same question in gamefaqs forum, and somebody informed me that when a male npc has the condition of samesex=1, he's suppose to use that line on a female as opposed to the condition of samesex=0.

So, if the condition is not suppose to be samesex=1, could there be something wrong with my copy of morrowind?

I tried to uninstall everything and delete all the mods to have a clean installation.
When I did that and checked arrille's dialogue again, it still has the same problem, any more ideas?

Thanks in advance for your replies.

maybe you can rewrite that part of his script

so instead of samesex=0 male samesex=1 female

you turn it around and set the male 1 and the female 2