Just seen this on the news today, thought it might be of some interest;
Twins have been born using a treatment called 'IVM' (In-vitro Maturation) at a clinic in Oxford. IVM is different to IVF in that immature eggs are removed from the ovaries. These are developed in the lab and then fertilized before been transferred back to the womb. This treatment is apparently cheaper and safer than IVF, in that it doesnt require stimulation drugs (So no danger of OHSS). It is apparently less successful than IVF and there are theoretical concerns about the maturation process damaging the eggs and leading to abnormalities. (Although IVM births so far show no problems).
See this link http://news.bbc.co.uk/2/hi/health/7058291.stm