necessity of mind or consciousness with semen and ovule in conception makes the sorig embryology different from western medicine.
though the semen and ovule are single cell, they should contain characteristics of all the five elements. five elements are earth, water, fire, air and space. and also the the semen and ovule should be free from defects of three humours.
when the mind or consciousness wandering in samsara sees scene of couple engaged in copulation, the desire to touch and hug arises from it. if the mind gets attracted towards man and feels jealousy for woman, a girl will be perceived, and vice versa. at the same time, the parents and and would-be-baby should have karmic connection.
after all the seeds of human life are gathered, earth gives a form, water contracts the form, fire ripens the form, air lets the form grow and space gives form a place to grow.