No doubt the fragile-X chromosome plays a small part in male disadvantage, but the point made in my review (Reference KraemerKraemer, 2000), referred to by Reference Branney and WhiteBranney & White (2008), is that the male is biologically less resilient. Reference Skuse, James and BishopSkuse et al's (1997) ingenious study of Turner syndrome shows that the X chromosomes inherited from mothers produce a different phenotype from paternally derived ones, but the bulk of male disadvantage probably derives from the Y chromosome.

Branney & White also err in summarising my argument. It is not that ‘this disadvantage is immediately mitigated once an infant's sex is known’ (p. 260). On the contrary it is compounded, in ways they themselves describe in their article. Prevailing assumptions about male resilience add ‘social insult to biological injury’ (Reference KraemerKraemer, 2000: p. 1612).