Let me illustrate the concern with an example.
There is evidence that largely for biological
reasons, women tend to have better survival
chances and lower incidence of some illnesses
throughout their lives (indeed even female fetuses
have a lower probability of spontaneous miscarriage).
This is indeed the main reason why women
predominate in societies with little or no gender
bias in health care (such as West Europe and
North America), despite the fact that more boys
are born than girls, everywhere in the world (and
an even higher proportion of male fetuses are
conceived). Judged purely in terms of the achievement
of health and longevity, this is a genderrelated
inequality, which is absent only in those
societies in which anti-female bias in health care
(and sometimes in nutrition as well) makes the
female life expectancy no higher than male. But it
would be morally unacceptable to suggest that
women should receive worse health care than men
so that the inequality in the achievement of health
and longevity disappears.c The claim to process
fairness requires that no group – in this case
women – be discriminated in this way, but in order
to argue for that conclusion we have to move, in
one way or another, away from an exclusive
reliance on health achievement.