Is it true?

Some of my friends insist that they can tell the sex of a plant by viewing the seedling... I can't. I toss my seeds and cross my fingers, is there any truth to this? Seedling in photo was an 8 ft. plus lady.Thanks and happy growing.

I read somewhere that someone " narrowed it down" by putting the seeds under a microscope and noting that the pointier seeds tended more often to be male and the seeds that have a small indented groove or dip in the surface of the seed tended more often to be female. There were photos of the two examples. I have no idea how scientific or accurate it really was though.