"FEMALE sperm", "male eggs" and "same-sex reproduction" - whether these terms fill you with hope or disgust, a reproductive revolution is already in progress. In a handful of labs across the world, biologists are trying to make genetically male cells develop into eggs, and female cells into sperm. If successful, their efforts might one day allow lesbian and gay couples to have children that are genetically their own.

Now Greg Aharonian, a patent analyst from San Francisco, is trying to patent the technologies that could make this possible. In part, Aharonian's goal is to stimulate debate. He argues that lesbians and gay men have a right to know about developments in biology that could allow same-sex reproduction. Aharonian also wants to undermine the argument that marriage should remain an exclusively heterosexual institution because its main purpose is procreation. "I'm a troublemaker," he admits.

In the US, where reproductive clinics are largely unregulated and religious conservatives are at war with gay rights campaigners over same-sex marriage, it should indeed cause controversy. Same-sex reproduction is also an issue in the UK, where... see more