A worker undergoing IVF treatment is not "pregnant" (and therefore is not protected from pregnancy-related discrimination) until the fertilised ova have been implanted in her uterus. However, a worker dismissed while on sick leave following collection of the ova for in vitro fertilisation, but prior to implantation, may be able to claim direct sex discrimination.

Dismissal for a reason essentially based on pregnancy (such as pregnancy-related sickness) is direct sex discrimination, even if a man taking a similar amount of sick leave would be dismissed, as only women can become pregnant. The ECJ has now ruled that the same logic can be applied to a woman undergoing this advanced stage of IVF treatment, given that it affects only women. The Court seems to be saying (albeit not that clearly) that dismissal for taking sick leave to undergo such treatment amounts to a reason essentially based on undergoing the treatment and is therefore direct sex discrimination. (Mayr, C506/06, ECJ)

As is often the case, the ECJ's reasoning is unhelpfully succinct and delphic, raising a number of questions. Would dismissals/detriment for absences to attend medical appointments at an earlier stage of IVF treatment also be direct sex discrimination? This presumably should be the case in relation to procedures which are particular to women and to the process of hopefully getting pregnant, for example the regular scan appointments needed to check on ova development.

What about those parts of the fertility treatment process that apply to the man, or the earlier, investigatory stage of infertility treatment, where both men and women will be subjected to various investigatory tests? Would any gender-specific test or treatment - or indeed other non pregnancy-related but gender-specific treatment (eg a prostatectomy) - also give rise to protection? The Court's reasoning does not expressly limit protection to procedures aimed at producing a pregnancy, but it must surely have been the Court's intention only to expand slightly the scope of the existing special protection for pregnancy to reflect the close connection between fertility treatment for women and pregnancy. Any wider view would represent a very significant change in the law.

A practical issue is whether employers should now allow female employees to take sick leave (subject to normal sick pay rules) while undergoing IVF treatment or whether leave can be unpaid. The UK statutory right to paid time off for ante-natal care is currently only available to pregnant employees. The cautious view is to permit sick leave to be used (subject to any more generous fertility leave entitlement provided).