I think IVF has gone about as far as it can. Next I expect that germ cells – sperm and eggs – will be derived from induced pluripotent stem (iPS) cells [cells that have the potential to develop into any of the body's cell types]. It will be possible to make iPS cells from skin cells, to make germ cells from these, and then combine them to make human embryos. It means every person, regardless of age, will be able to have children: newborn children could have children and 100-year-olds could have children. It could easily happen in the next 30 years. I have no idea if the technique will be used, but it means you could have millions of gametes that could be combined at will. I have no idea what kind of moral value or rights we would give to those embryos. We'll probably go through the same agonising we did with IVF. It could be terrible to begin with, but then it'll become a fact of life. Maybe 20 to 30 years from now we'll read that someone made 20,000 embryos and studied their development, and we'll decide it's OK.