There are around 44% of the population who are Group O blood group and about 42% who are Blood Group A. Now not only does this affect your diet but also your fertility.
Scientists have discovered for the first time that a woman's blood group could influence her chances of getting pregnant.
Researchers who tested a group of women seeking fertility treatment found those with the blood type O appeared to have a lower egg count and poorer egg quality than others.
The study of 560 women, whose average age was just under 35, found that those with blood type O were more likely to have higher levels of 'follicle stimulating hormone' (FSH) than those with type A.
Fertility experts regard a high FSH level as a key indicator of having a low egg count, which is known as "diminished ovarian reserve".
As a woman's ovaries run out of eggs in her 30s and 40s, production is stepped up to encourage more follicles to be made.
The study found that women who were blood type O were twice as likely to have an FSH level above 10 - commonly regarded as the threshold between normal and raised levels - as those in any other blood group.
It did not quantify how much more difficult women with blood type O could find it to conceive.
People with blood group A carry the A antigen, which is a protein on the surface of the cell, but this is absent in people with O type.
The lead author, Dr Edward Nejat of the department of obstetrics and gynaecology at the Albert Einstein College of Medicine in New York, said this was the first time a potential link between blood type and fertility had been identified.
He is presenting his findings, based on women undergoing fertility treatment at the Yale University IVF programme and the Montefiore Institute in New York, at the annual American Society for Reproductive Medicine (ASRM) conference in Denver on Tuesday.
He said: "Those with blood type O were twice as likely to have an FSH level over 10 than those with blood types other than O.
"We found that women with the A blood group gene were protected from this effect of diminished ovarian reserve.
"Patients with blood type O seeking infertility evaluation at these centres have a higher likelihood to be diagnosed with elevated FSH and hence manifest diminished ovarian reserve."
The only problem is most people do not find out what their blood group is until they get pregnant. Therefore if you are thinking of leaving pregnancy till later on this may be something to bear in mind.
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