Britain's fertility regulator could allow doctors to create the first babies to have three people's DNA from next April after the government pressed ahead with plans to legalise the procedure.

The technique, known as mitochondrial transfer, offers hope to families affected by a wide range of diseases, such as muscular dystrophy, caused by faulty DNA being passed down from mother to child.

The experimental procedure replaces faulty genetic material found in mitochondria, the small cellular batteries that power human cells, with healthy DNA taken from a donor woman.

One in 6,500 children in Britain each year are born with a serious mitochondrial DNA disorder. Many of the conditions affect power-hungry organs such as the brain, muscles and heart, and often worsen with age. Many children are disabled and die young from their illnesses.

The Department of Health announced plans on Tuesday to press ahead with regulations following a three-month public consultation which drew 1,850 responses. The draft regulations are due to go to parliament for debate in the autumn, and could be law by April next year.

But there are several hurdles that could delay the decision in parliament. Britain's fertility watchdog, the Human Fertilisation and Embryology Authority (HFEA), must work out an approval process for families who wish to have the procedure. Meanwhile, an expert panel convened by the regulator is awaiting the results of more scientific experiments on the safety of the technique.

Once the HFEA is satisfied that it can proceed, the regulations will be looked over by the government's joint committee of statutory instruments and the secondary legislation scrutiny committee before parliament will have its say.

"I'm happy that this is moving forward," said Doug Turnbull, who developed the procedure at the Wellcome Trust centre for mitochondrial research at Newcastle University. "The important thing now is that it gets into parliament this session.

"My fear is that if this is delayed, we are into a new government, and we cannot know the shape or support of that government, and it could be delayed for a long time. Patients in the UK would miss out."

Mitochondrial transfer is controversial because the healthy donor DNA is inserted into IVF embryos. That means the genetic material is not only carried by the child that grows from the embryo, but is passed down the female line to all future generations. So far there is no evidence that the procedure is dangerous, but unknown side-effects could emerge and affect all of the generations that carry the donor DNA.

The amount of mitochondrial DNA that comes from the donor is minuscule – just 37 genes, or about 0.2% of a human's total genetic makeup. These genes are only involved in making energy for cells, and are held separately from the 23,000 genes found in cell nuclei that affect appearance, behaviour and other traits.

Families affected by mitochondrial diseases are often oblivious until one of their children is diagnosed with a condition. To avoid having other children who are at risk, they must either adopt or have IVF with donor eggs.

Turnbull said: "My patients are making choices all the time. Some don't want to have more children because of the risk. Others have egg donation. There is going to be a risk with any sort of new technique, but everything that's been done so far suggests the risks will be less than with passing these diseases on."

Jeremy Farrar, director of the Wellcome Trust, said: "As the government's latest consultation has again shown, there is broad public support for making mitochondrial replacement therapy available to patients. There is now no excuse for the government not to table regulations for debate as soon as parliament returns this autumn, so that the HFEA can licence clinics to treat affected families without delay once it is satisfied that any risks are acceptable."

Robert Meadowcroft, of the Muscular Dystrophy Campaign, said: "It is now up to the government to ensure that these regulations are considered and approved by parliament before the next general election in May 2015, or risk losing the progress that has been made towards taking this pioneering technique forward. We need to see a firm commitment to debating this issue in parliament before the end of the year."

Sarah Norcross, director of the Progress Educational Trust, a charity that promotes public engagement in genetics, assisted conception and embryo research, welcomed the government's announcement, but said the process was taking too long. "The people who oppose this will be saying it's too quick, why the rush, but inevitably the delay is passed on to people who want to avoid passing on these devastating conditions to their children."