After the cancer mouse row, the designer sperm

TWO AMERICAN scientists have invented a way of correcting defective genes in sperm so children inherit only the 'healthy' ones.

The University of Pennsylvania in Philadelphia is trying to patent the technique with the European Patent Office, but most European countries have ruled that 'germ-line' gene therapy - where new genes are passed to subsequent generations - is unacceptable. In some countries it is illegal.

The genetic engineering of sperm is the latest controversial biotechnology patent to be considered by the Office. After protests across Europe, the Office is reviewing a decision to allow a patent (also sought by an American university) on a mouse designed in the laboratory to contract cancer.

Under the European Patent convention, patents can be refused on the grounds that they might be contrary to morality or to public order.

Today's issue of New Scientist magazine says Ralph Brinster, professor of physiology at the University's Veterinary School, and Jim Zimmermann developed the sperm process for animal breeding. However, the patent specification is broad enough to include applications 'where the said animal is human', the magazine states.

The technique involves removing sperm-producing cells, known as spermatogonia, from the testes and then irradiating the testes to destroy any remaining sperm or spermatogonia. New genes can then be inserted into the spermatogonia removed earlier and altered cells put back into the empty testes.

The genetically engineered spermatogonia would mature and produce healthy sperm which would carry the designer genes into any child the man fathered.

Inserting 'designer genes' into animals and plants for propagation is routine in research laboratories and commercial companies. The first successful gene therapy on a human was in September 1990 when a girl was treated for an immune system defect.