Evidence of oxidative stress can appear under other conditions, including exposure to certain environmental pollutants or infections in the urinary genitaltract.
It may be provoked by infection with Chlamydia trachomatis, a sexually transmitted denizen of the genitaltract, and Ureaplasma urealyticum and Mycoplasma fermentans, two other inhabitants of the genitals.
Mr Dilly Anumba, a consultant obstetrician at Sheffield University who has recently published work showing that TLRs are present in the female genitaltract, said Professor Bennett's theories were logical and well worth pursuing.