A stingray's sex can be determined fairly easily based on the presence or absence of claspers, two "penises" connected to the inside of the pelvic fins of male rays. They are usually about the size of your pinky finger on mature specimens and are rolled up into hollow tubes. On juvenile rays, they look like tiny nubs and are a bit harder to identify, but it is still possible to tell males and females apart at this stage. You just need to look a bit closer.
The eggs are fertilized internally after the male inserts one of his claspers into the female's cloaca, which serves dual purposes in defecation and reproduction. In order to accomplish this, the male must grab hold of the female's disc with his mouth and roll underneath her, so that their bellies are facing one another. The actual sex act usually lasts no longer than a couple of seconds. Females can sometimes sustain slight injury during mating when the male bites her, which is why they have evolved thicker, more durable skin than males. If you are trying to breed rays, be sure to pick a male that is the same size or slightly smaller than the female, as a larger male can overwhelm and seriously injure the female in his overzealous mating attempts
(tu yg cm sengat yg ada dua kat dlm gambar tu yg menentukan jantina pari - jantan ado 2 )