RICHMOND, Va. (AP) - Scientists are confirming the second case of a "virgin birth" in a shark.

The Journal of Fish Biology reports that scientists say DNA testing proves that a pup carried by a female Atlantic blacktip shark in the Virginia Aquarium & Marine Science Center contained no genetic material from a male.

The first documented case of asexual reproduction, or parthenogenesis, among sharks involved a pup born to a hammerhead at an Omaha, Neb., zoo. Shark scientist Demian Chapman says "it is quite possible that this is something female sharks of many species can do on occasion."

Scientists say absent the chromosomes present in the male sperm, the offspring of an asexual conception may be at a disadvantage for surviving in the wild.

Virgin birth has been proven in some bony fish, amphibians, reptiles and birds, and has been suspected among sharks in the wild.