Sir

Your Editorial 'Life after SuperBabe' (Nature 454, 253; 2008) and Special Report 'Making babies: the next 30 years' (Nature 454, 260–262; 2008) summarize the far-reaching social and ethical implications that arise from progress in in vitro fertilization (IVF) and stem-cell research. One aspect that has so far received scant attention is likely to have a substantial impact on both legal practice and everyday behaviour, at least for the rich and famous.

Scientific progress should eventually enable us to derive both sperm and egg from differentiated cells, using a combination of induced pluripotency (iPS) and directed differentiation (see 'New sources of sex cells' Nature 452, 913; 2008). Before too long, it may be possible to collect a few hundred skin cells secretly from a used towel, a toothbrush or even an empty glass of water, then reprogram and differentiate these cells into sperm or egg. IVF could then be used to produce a child whose genetic parents are the involuntary tissue donors.

Such 'stolen' parenthood might be viewed as a dubious and expensive practical joke, if a child were to be conceived whose genetic parents were, say, Nicolas Sarkozy and Angela Merkel, derived from laundry at a G8 summit. But the widespread use of genetic evidence in paternity suits could provide a serious financial incentive for a woman to bear an iPS-derived IVF child whose genetic parents are herself and, say, Paul McCartney or Mick Jagger, presenting a lucrative opportunity to sue the genetic father for support for his 'illegitimate' child. And even if such financial incentives were to be removed through changes in legal practice, the problem of stolen parenthood is likely to persist, given the significance that many people assign to kinship with famous people.

Two societal reactions might follow. First, abuse of human biological material in a wide sense is likely to become a statutory offence, generalizing the prohibition of secret genetic testing that has already been enacted in many countries. Second, persons who perceive themselves as potential victims of stolen parenthood might sterilize whatever waste they dispose of, unless of course they see their status soaring by allowing their parenthood to be stolen by as many groupies as possible.