It defaults to the masculine ending when referencing a noun related to males and females in one group.

It defaults to the masculine ending when referencing a noun related to both males and females in one group.

But this might be an exceptional case, for I doubt not that many a child in England, and possibly even boys, with an unwonted masculine ending, might be called after the noble woman who freed her people from the tax— "And made herself an everlasting name."

A line has a masculine ending when its last syllable is stressed; when it ends, for example, on words or phrases like behold', control', no more', begone'.

Marriage of Figaro, 111. masculine ending, 57.