the qualified candidate is male
First of all, presbyteros—the word used for “elder”—translates to “older man or woman,” so it’s not really gender-specific.
Secondly, consider the context. English has natural gender, where the ideas of masculine and feminine translate directly to man and woman. But Greek is a language with formal gender, where each noun/verb/adjective/etc has an inherent gender but isn’t tied to the ideas of man and woman.
Lastly, the fact that this was written during a time and place where patriarchal societies were common means that masculine words were the default but may or may not have been indicative of specifying males only. (More info about that here: http://www.bible-researcher.com/inclusive.html)