Gender differences

It became clear that gender could influence biomedical research results

As diseases can affect the two differently - Certain diseases affect one gender more than the other

• Women generally have bigger pelvises - Men generally have more skeletal muscles and bigger frames

80% patients are women

3-fold more common in women than men

2-3 times more common in women than men

• Possible connection to women producing less serotonin (neurotransmitter) - though some peoples doesn’t improve with antidepressants (boosts serotonin)

Sex-based differences also present in incidence & expression of schizophrenia, PTSD, panic disorder, etc.

• Societal • Genetic • Effects of the sex steroids

• Lifestyle/behaviour - Some female athletes show very similar physiological traits as men • Environmental • Healthcare

Linked to x- or Y- chromosome

It can be hard to treat transgender people because some treatments are gender based and they are truly the opposite gender than is at face value

• Androgens, estrogens and progestins - All present in both males and females

Physiologically important in both males and females

Sexual differentiation - all start off as female in womb

Child, adolescent & young adult

• Variation with menstrual cycle in women - Pregnancy

Some cancers target one gender rather than the other because of the hormones they target

Causes abrupt drop in estrogen & progesterone

Gradual decline in testosterone with aging in both men & women - After the menopause the difference in physiology and hormones becomes smaller, as men and women become more similar

Men have: • Greater bone mass • Greater muscle mass • Lower %bf - typically because women have higher due to reproductive system

• Men have bigger hearts and lungs • Men have bigger brains • Gastrointestinal system

5-10mmHg higher in men than women - Difference disappears after menopause

Lower in men than age-matched women