The process involves injecting an empty cow or rabbit egg with human DNA. A burst of electricity is then used to trick the egg into dividing regularly, so that it becomes a very early embryo, from which stem cells can hopefully be extracted.

Scientists say the embryos would not be allowed to develop for more than 14 days, and are intended to address the shortage of human eggs available for stem cell research.

Under the new laws, in-vitro fertilization clinics will no longer have to consider the need for a child to have a father when deciding whether to offer treatment to lesbian couples.

Those opposed to the proposal insist the change fails to acknowledge the role of a father in a child's life.

Opposition Liberal Democrat lawmaker Evan Harris said he had hoped the debate would allow him to put forward proposals to extend the right to have an abortion to women in Northern Ireland — where terminations are not permitted.

Nadine Dorries, a lawmaker with the main opposition Conservatives who attempted in May to reduce the upper time limit for abortions in Britain, said the government had ducked a potential fight over terminations.

British lawmakers voted in May in favor of keeping the current upper time limit for abortions of 24 weeks.