I'm no Dr.. But when I had my daughter I did the Chinese calendar and it was right for me...
I'm in my 2nd pregnancy now I haven't had an ultrasound yet. I did the banking soda test and it said boy , I read the Chinese calendar and it said girl.... BUT , my mother in law had her cards read and the lady told her she sees me having 2 babies twins.
So.......... Were just waiting on my ultra sound