>
Is that a major difficulty for translators?
Oh, yeah...

Most of the languages of the world modify their nouns ( and even their pronouns, verbs, articles, etc. ) according to the gender of the subject.
A simple word like ?Friend? can be written as
Freund / Freundin ( in German ),
Ami / Amie ( French ),
Amigo / Amiga ( Portuguese ),
Chaver / Chavera ( Hebrew ),
Amico / Amica ( Italian ), and even
Prijatelj / Prijateljica ( in Serbo-Croatian )...
And naturally, it is regarded as
extremely impolite to address a woman as a man or vice-versa.
Therefore, if you want a Spanish vBulletin, for instance, it should display
?Bienvenido, John!? for the ?Welcome? link - but it
also must display
?Bienvenida, Mary!?...