New Delhi, Oct. 10: A dozen times over the past one year, fertility specialist Indira Hinduja has reached into a canister of liquid nitrogen and pulled out thin plastic straws that hold live human embryos frozen at minus 196 degrees Celsius.

The embryos are microscopic, smaller than a pinhead, just eight cells in all.

Each time, Hinduja and her research collaborator Deepa Bhartiya have waited for the embryo to thaw, grow and yield stem cells ' an extraordinary class of cells that medical researchers hope to use to treat cancer, diabetes, heart disease and brain damage, among other illnesses.

But after a year of trying, they don’t have a single set of embryonic stem cells.

Now they want to try and harvest stem cells from fresh human embryos, not frozen ones. Bhartiya and Hinduja are among scientists in India who want national ethical guidelines revised to allow the creation of human embryos exclusively for research.

Every embryo used for stem cell research in the country today comes from test-tube baby clinics. It belongs to parents who’ve already had a test-tube baby and consented to donate spare embryos for stem cell extraction.

“This restriction of using only frozen embryos slows down research,” said Bhartiya, assistant director at the National Institute of Reproduction and Reproductive Health, Mumbai, that has launched India’s first facility for human therapeutic cloning.

Because take-home-baby rates are abysmally low, fertility clinics store extra embryos just in case a pregnancy doesn’t work out and a couple needs a new embryo. The embryos are stored in cold liquid nitrogen but remain viable for growth.

“But pulling embryos out of this frozen state is an inefficient way to get stem cells,” said Satish Totey, the director of the stem cells centre at the Manipal Hospital, Bangalore. The tiny embryo has to thaw, grow into a 100-cell blastocyst, and develop an inner core of cells that serve as progenitors for stem cells.

At each stage, scientists can lose embryos. “Some embryos get destroyed during thawing. Some don’t make it to the blastocyst stage. And some don’t produce stem cells,” says Bhartiya.

Scientists believe these embryo losses spring from changes during the thawing process. With fresh embryos, they believe, chances of getting stem cells will improve. “Such procedures are allowed in South Korea and the UK. India’s losing time,” Totey said.

Government scientists who monitor medical ethics have reacted with caution. “We need a wide public debate on this,” said Vasantha Muthuswamy, head of ethics and biomedical sciences in the Indian Council of Medical Research. The council and the department of biotechnology are revising guidelines for stem cell research.

Embryonic stem cells lack identity but, in principle, can be coaxed to turn into any type of cell in the body. Scientists hope to rejuvenate a damaged brain, heart, liver, pancreas and other organs by implanting brand new cells derived from embryonic stem cells.

However, many scientists in the field have cautioned that embryonic stem cell therapy will not be available for routine medical applications for at least the next five years.

While couples at fertility clinics might consent to donating embryos before they are frozen, scientists say, there are not enough spare embryos. However, a big increase in the number of fresh embryos might be possible through voluntary egg donation for embryo creation.

The proposal hasn’t gone down well with health activists. “It is shocking. Everybody wants to jump into the race for stem cells,” said Renata Klein, associate professor at Deakin University in Australia who has studied the impact of medical technologies on women’s health.

“The donors will always be poor and uneducated women who might seek compensation, but won’t be in a position to understand the risks involved,” said Renu Khanna, an activist with People’s Health Movement.

The process of donating an egg, while generally considered safe, does carry a small risk of complications like bleeding, scarring, pelvic swelling.

The scientists seeking revised guidelines concede their suggestions are controversial.

Hinduja says it is possible to regulate egg donation through safeguards designed to avoid exploitation of women. “There are ways to do this transparently, by clearly explaining to potential donors how they might contribute to research,” she said.

“In the end, society must decide. People should understand the potential benefits and risks of such procedures and then decide. But science will continue to progress.”

Now, Bhartiya relies on spare, frozen embryos donated by parents at the clinic of Hinduja, who produced India’s first scientifically documented test-tube baby in 1986.