On the critical assessment of the impact of the recent European Union Tissues and Cells Directive.

In this commentary it is argued that David Mortimer's contention (Mortimer, 2005) that 'there are grave problems with the feasibility, effectiveness and likely adverse impact of applying clean room and air quality standards to assisted conception facilities, especially IVF laboratories', as envisaged in the European Union's Tissues and Cells Directive (2004), is fully justified. As he says, 'effective regulations need to recognize what is impossible, what is possible and what is realistic'. The Directive, while necessary in principle, does not take into account the fact that what may appear to be ideal from a narrow technical point of view may, in fact, in a larger context, defeat its purpose by actually being harmful.