By urinating on wheat and barley seeds. If barley grew, it meant that it was a male child. If wheat grew, it was a female child. If neither grew, it meant that she wasn’t pregnant.
Guessing is right 50% of the time, right? Nonetheless, in modern testing the barley pissing had a 70% success rate.
Credit and link: OMG facts
A Timeline of Pregnancy Testing - History.NIH.Gov, yes, a government website is running, one of the few the administration did not shut down out of spite.
Source: Ancient Egyptians had a pregnancy test that predicted the sex of the baby 70% of the time! - OMG facts
