Please quote the Scripture that supports your man-made beliefs
Luk_1:36 And, behold, thy cousin Elisabeth, she hath also conceived a son in her old age: and this is the sixth month with her, who was called barren.
We already have a word for cousin...
Mar_6:4 But Jesus said unto them, A prophet is not without honour, but in his own country, and among his own kin, and in his own house.
We already have a word for kin...
Mat 13:56 And his sisters, are they not all with us? Whence then hath this man all these things?
Sister, like brother means natural brother/sister or ecclesiastical brother or sister...