Studies have shown that females have more white blood cells, the parts of the blood which produce antibodies — natural proteins which neutralise bacteria and viruses.
Disease therefore progresses faster in men — and tends to take hold earlier in their lives.
But women's powerful immune systems can sometimes attack themselves, making them more prone to autoimmune diseases such as rheumatoid arthritis, lupus and multiple sclerosis.
If A nasty bug does penetrate that iron-clad immune system, women still have the advantage: they fight off sickness faster.
It's no surprise that adult women's bodies have high levels of oestrogen and progesterone, the female sex hormones.
This flexibility makes pregnancy possible — and makes women stronger and better at battling disease.But women have more connections going from left to right across the two halves of the brain, which gives them an advantage in pulling together information from different sources and drawing logical conclusions.