The most obvious answer is that many lesbians become lesbians because they have low estrogen levels. Low estrogen levels through puberty probably retard normal psycho-sexual development. Low estrogen also results in high levels of lipoprotein lipase. High levels of lipoprotein foster the storage of fat.
Where’s my government grant?
Save some taxpayer money. Probably it is because they eat too much and exercise too little. Duh!