Mother of family has become "Father" (but still female) by some mistake

Somehow I’ve got a family which has got twisted. I think I may have put mother’s maiden name in as surname for first child, but that has persisted and Mother (although still feminine) has become “Father” and Father has become “Mother”. I have corrected the surname now for all the children but the parents remain wrongly labelled.

How can I correct?

Og to the pencil and then swap Father and Mother.

THANK YOU! I haven’t used that magic pencil yet. I’ll make a note of the things it can do!

Ancestry Treeshare somehow causes that sometimes for me.

That’s interesting. I just assumed it was something I’d done! Now I’m trying to remember which family got swapped and if I had done a tree share, but I think not. If I had, it would have been My Heritage, not Ancestry. They keep sending possible matches!