How did gender roles originate?

In most conservative societies, including India, there is a great deal of rigidity concerning the roles of men and women in various walks of life. There are thin red lines that either sex should not cross, especially in social and economic matters. So, how did this demarcation of roles between the sexes happen? 

In her interesting Al-Jazeera piece, Alison Booth writes about how the relative bargaining power of men and women has evolved.

"Millions of years ago our ancestors began to colonise what Seabright terms "a very risky evolutionary niche: the long childhood". This needed more cooperation between the sexes in order to ensure the survival of the offspring, and sex became not merely reproduction but also a cooperative venture.

"We all know the profound differences between male and female sex cells. Women's are large, scarce and relatively expensive to make. Men's are small, abundant and cheap to manufacture. Because of the relative scarcity of women's eggs, and their costliness once fertilised, women have to be selective about the source of the sperm. A woman carries and nurtures the foetus in her body for over nine months. Once the baby is born, she has to feed and protect the child for a long time afterwards. She does not want to waste her opportunities on unsuitable men; they have to be screened out. So we have female selectivity on the one hand and male persistence on the other hand." (End of excerpt)

Read the complete article here.