380024 06: A close up of a microscope slide taken at the Reproductive Genetics Institute''s Chicago laboratory shows a similar controversal procedure conducted recently by the Reproductive Genetics Institute in Chicago. A team of research doctors recently transplanted stem cells taken from the umbilical cord of a baby boy whose embryo was chosen specifically to save his six year old sister who suffers from Franconi''s anemia, an inherited disorder that causes a massive failure of bone marrow cell production and which is usually fatal. The sister, Molly Nash, is recovering from the $100,000 procedure at a Minneapolis hospital. Critics of the procedure warn that the practice of cell transplantation raises ethical issues and that "creation for donation" might one day lead to "designing your descendants" for pre-screened traits such as eye color, strong limbs or intelligence. (Photo by Tim Boyle/Newsmakers) Displaying the first examples of animals with reversed genitals, researchers have discovered cave insects in which the females have penis-like genitals and the males have vagina-like organs. (Photo by Tim Boyle/Newsmakers)

Hartford (CBS CONNECTICUT) — Displaying the first examples of animals with reversed genitals, researchers have discovered cave insects in which the females have penis-like genitals and the males have vagina-like organs.

Scientists discovered the little-known cave insects from extremely dry caves in Brazil. Of the four species studied in the Neotrogla genus, the females possessed penislike genitals labeled gynosomes, and the males had vagina-like phallosomes – the first ever cases of extreme reversal of sex roles.

“Neotrogla species constitute the first cases in nature in which genitalia are reversed,” study co-author Rodrigo Ferreira, a cave biologist at the Federal University of Lavras in Brazil, told Live Science.

The penis-like organs present in the females are relatively large in comparison to the insects, about one-seventh the length of the insect as a whole. The insects were found to engage in intercourse between 40 and 70 hours, with the females inserting their gynosomes into the male organs.

Published in the Massachusetts-based journal, Current Biology, the scientists findings show a “completely novel structure in evolution,” study author Kazunori Yoshizawa told Live Science. “Evolution of such novelties is exceptionally rare, maybe comparable with the origin of insect wings.”

There is no biological structure known anywhere else among females in the animal kingdom analogous to the insects’ gynosome, Yoshizawa told Live Science.

Due to excessive amounts of nutritious semen that the males produce, the resource-poor caves cause the females to copulate at much higher rates, and with greater intensity.

“It is very likely that female Neotrogla can coercively grasp and copulate with a reluctant male,” Yoshizawa told Live Science. “In animals, coercive mating is generally an exclusive feature of males.”

The scientists are continuing to explore how males respond to coercive mating from the females, and the researchers note that dozens of new species are turning up in the Brazilian caves.

“This indicates the huge potential that Brazil possesses regarding cave fauna,” Ferreira said. “Brazil might have more than 150,000 caves.”

But study author Ferreira said that many of these caves and rare insects have become seriously endangered.

“The Brazilian laws regarding cave protection have changed in recent years and now the caves, which used to be protected, are under risk,” Ferreira said. “Many new species, some of which could bring huge advances for science — biology, evolution or even some of biotechnological interest — are threatened. Many species are under the risk of extinction even before being discovered.”