The Daily Telegraph (Sydney, Australia)
February 13, 2003

Designer Foal Made In A Lab
by Simon Benson

THREE months old and oblivious to her fame.

A healthy black filly named Ballerina has become the first foal in the world to be produced by sex-selected embryonic transfer.

In other words, scientists created her in the laboratory from sperm and an egg, selected her sex, then implanted her as an embryo into a surrogate mare.

It is the first time in Australia that a sex-selected foal has been born.
It is also the first time that both techniques have been used to produce offspring from a horse.

Ballerina was born to one of Australia's leading polo pony mares owned by James and Suzie Ashton near Cowra in central NSW.

She was born on December 11 and has remained a secret until now.
"The ability to choose the sex of a foal prior to conception has long been a dream of horse breeders, especially breeders of sport horses such as polo ponies, quarterhorses, showjumpers, dressage and eventing horses," Sydney University's veterinary science foundation said.

The faculty of veterinary science's Reprogen unit collaborated with private US company XY-Inc to develop the technology. The same team last year broke ground using the technique with sheep.

Using a process known as cytometry flow, Dr Chis Maxwell, Dr Fiona Hollinshead and the university's Dr Lee Morris identified differences between X and Y chromosome-bearing sperm.

Sperm have slightly different DNA content whether they carry an X or Y chromosome.

The team then created a female embryo which was implanted into the uterus of a surrogate mare.

The benefit is that it lets valuable mares produce offspring many times without having to go through pregnancy. This could also be particularly useful in its application to endangered species programs.

Sex-selection is already used all over the world, but it has never been combined with embryo transfer successfully before.

It has commercial potential, particularly for breeders. But Thoroughbred Breeders Australia president Richard Turnley said the technology would not be allowed to be used in the racing industry.

"We are 100 per cent opposed to it. Any progeny born of embryo transfer cannot be registered in the stud book," he said. "That's our position. And the International Stud Book Committee have a parallel ruling."