While this website's meaning for the male name
John is "
Yahweh is gracious", I have also heard it interpreted as "gift of God". I have heard that both meanings refer to the pregnancy of
Elisabeth,
John the
Baptist's mother, being a gift from God because she was 'aged' and considered too old to conceive.
If you choose to follow that interpretation, I suppose any simple feminine equivalent of
John would serve:
Jane,
Jean,
Jeanne or
Joan. Or if you change your mind and decide to go for a more complicated name:
Jeannette,
Johanna,
Siobhan,
Sinead or
Sine.