The 14-day limit should be extended to 28 days Appeared in BioNews 1083 The '14-day rule', initially proposed in 1979 in the USA, was first recommended in the UK by the Warnock Committee in 1984. It limits research on intact human embryos to 'prior to 14 days' gestation or the beginning of primitive streak formation' and is part of the Human Fertilisation and Embryology Acts of 1990 and 2008 (HFE Acts). This legislation has been successfully implemented in the UK, but also in several other countries (eg, Australia's Research Involving Human Embryos Act 2002). It is followed in jurisdictions ...