Don't know the reason but have male & female alters. Before we knew we were DID, several times we were called by doctors' offices to go repeat blood work or other tests. When it happened after our dx, questioned the nurse on why we had to repeat. Got either a don't know or probably a lab error reply. T suggested we ask the dr. directly. The dr.,obviously a little ticked off himself at not having 'correct ' results, said .. these are obviously male values.