I recently came across an unusual eclipse IDE error: Cannot specify a gender for a gender neutral language
In the 7 years I've been doing Salesforce work, that error was a first. Fortunately, I found some folks who have also run into this -
https://developer.salesforce.com/forums/ForumsMain?id=906F00000008uyaIAA
Turns out if you are toggling between a language like Spanish/French and English while building something in Salesforce, you might need to delete the <Gender> tag in the object metadata.