Spontaneous sex change is relatively common in lower aquatic species with simple reproductive systems. Half of the creatures will change from male to female and the rest will switch the other way. Regardless of which way they change, the gender-altering creatures can still successfully reproduce afterwards.

“They are mother and father in the same lifetime. That is the staggering thing about it,” he added.

Allsop, who reported the findings in the science journal Nature, said the creatures reach 72 percent of their maximum size and then something triggers the sex change, but they are not sure what it is.

“Our results suggest that the underlying factors favouring sex change are remarkably similar in all animals. More generally, it is amazing that simple theoretical ideas can potentially explain a universal characteristic of growth and reproduction across such different groups” West added in a statement.

Regarding the puberty gene discovery, “It’s a wonderful surprise,” says Stephanie Seminara of Massachusetts General Hospital in Boston, who helped to determine the gene’s function.  Drugs that alter the gene’s activity could stifle or boost fertility, she says. This could help those who experience puberty abnormally early or late.  GPR54 blockers may also help to treat prostate cancer, suggests hormone specialist Larry Jameson of Northwestern University in Chicago. Such drugs could dampen the effects of testosterone, which can swell tumour size.