asked Her Majesty's Government:

Further to the Written Answer by Lord Darzi of Denham on 24 June (col. WA 227), how many outgrowing embryos cultured for more than 14 days are required to derive one embryonic stem cell line; and how this compares to the efficiency of embryonic stem cell derivation using conventional approaches used by Professor Sir Martin Evans in mice and Professor Jamie Thomson with human embryos. [HL4491]

The department is not in a position to form a view on the efficacy of stem cell derivation from outgrown embryos.