I think a lot of us change the gender to suit the singer. Even though, traditionally, the gender of the singer is not supposed to matter, the singer being a vehicle & not necessarily telling a first-person story, a lot of audience members don't understand that. Particularly in today's gender-polarized & often homophobic situations.
Sometimes it's pretty difficult - there are a number of songs using gender-specific words that don't have an easy-to-rhyme alternative. For example, "man" can usually be bent into "woman" despite the extra beat it inserts, but if the lyrics do something like rhyme "girl" with "whirl" or "world" it's more difficult to alter the words.