Jenny Graves from Canberra University's Institute for Applied Ecology, said that the process is likely to happen within the next five million years but could have begun in some isolated groups, the Herald Sun reported.
Graves, who first made the prediction some years ago, has been studying sex-determining genes in Australian animals so as to shed light on human genetics.
She said that people think that sex is so important that it wouldn't change a lot but it changes all over the place and the Y chromosome sort of self-destructs.
Y is always in the male and is active mostly in the testicles to make sperm.
Graves asserted that is a "very dangerous" place as there is a lot of cell division going and with every split there is a chance for a mutation or gene loss.
She said that the X chromosome is all alone in the male, but in the female it has a friend so it can swap bits and repair itself but if the Y gets a hit it's a downward spiral.
Graves said that the X has about 1000 genes left, too many relating to sex and intelligence and the smaller Y started with about 1700 genes but only has 45 left, and that's mostly "junk."
She added that if humans don't become extinct, new sex-determining genes and chromosomes will evolve, maybe leading to the evolution of new hominid species similar to what happened in the Japanese spiny rat, which had survived the loss of its Y.