How exactly are these gender swapped?

Luc is the genderswapped, although it's difficult to tell. The artist only does genderswaps.

http://www.pixiv.net/member_illust.php?mode=medium&illust_id=3175557 this is the link to the original on pixiv.

The tag "性転換17" is "sex reversal 17" AKA genderswap.