A “genetic contraceptive” that could interfere with the make-up of women’s eggs during ovulation and which is designed to have none of the side-effects of traditional hormone-based pills is being developed by scientists.
The new approach, the researchers say, should make it impossible for sperm to fertilise women’s eggs. If the technique can be made to work it will mark the first advance in chemical contraception since the first stages in the development of oral contraception work begun by Carl Djerassi nearly 60 years ago, which led to the Pill. Because a genetic contraceptive will not flood the body with sex hormones, it will avoid many of the side-effects caused by conventional birth control pills, the researchers believe.
Traditional oral contraceptives, which are based on the steroids progesterone and oestrogen, have been linked to an increased risk of blood clots and certain cancers, and may also affect mood and libido and cause weight gain. The new contraceptive relies on a technique called RNA interference, which uses tiny fragments of genetic material to block the activity of genes in the body. The process is so powerful it was lauded as a revolution in medical science last year, when two American scientists, Andrew Fire and Craig Mello, won the Nobel prize for their work on it. “If you could block this in women you could prevent pregnancy from occurring,” said Zev Williams from Brigham and Women’s Hospital in Boston. “For women who use the pill just as a contraceptive, a non-hormonal approach would be wonderful. You could get all the benefits without the nausea, the headaches, the mood alterations, and the raised risk of thrombosis, stroke and heart attacks.”
The scientists hope to begin full tests on animals within five years. If they consider the method works safely, a product, probably in the form of a suppository or skin patch, could be available within 10 years. Ian Sample
Astronomers near finding ‘second Earth’
Astronomers may be on the brink of discovering a second Earth-like planet, a find that would add fresh impetus to the search for extraterrestrial life, according to a leading science journal. Planet hunters have spotted more than 200 planets beyond our solar system, but the vast majority are hot, Jupiter-sized planets that would dwarf Earth and are almost certainly lifeless.
Writing in the US journal Science, astronomers from six major centres, including Nasa, Harvard and the University of Colorado, outline how advances in technology suggest scientists are on the verge of being able to detect the presence of small, rocky planets, much like our own, around distant stars for the first time. The planets are considered the most likely havens for extraterrestrial life.
“It could happen almost any time now. We have the technological capability to identify Earth-like planets around the smallest stars even now,” said Dave Latham, a co-author on the paper at the Harvard-Smithsonian Centre for Astrophysics. He said missions such as Nasa’s planned Kepler space observatory, which is due to launch in early 2009, would have a high chance of finding Earth-like planets if they are out there. Ian Sample
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