"Male". To say "girl", "keiki wahine" changes a little to become "kaikamahine". I don't know why it changes. You'll see similar patterns in other words, where the word alone is genderless and you can add kāne or wahine to give it a gender.

Nope. In front of "kaikamahine" it would be "ke" even though a "girl" is feminine. There aren't masculine and feminine articles in Hawaiian. It's sort of like English "a" and "an" which changes depending on what letter the next word starts with. "The" is "ka" in front of most letters, but becomes "ke" in front of k, e, a, and o. So in front of "wahine" you would use, "ka", but in front of "kāne" and "kaikamahine" it is "ke".