I think that it is reasonable for women to avoid "lunch alone".

What does it mean?

"Just several ten thousand years ago, both men and women save their life and family with getting foods by men and caring their children by women."

"Hm-hm"

In order to get foods for men, they have to be long absent from their home. The women have to save their and children life for the period.

"And?"

"The women should have made them groupy, especially there were some dangers, for example, robbing them their foods during lunch time.

"And?"

The "lunch alone" was a really danger for women, and a special woman who tried to do "lunch alone" could not survive and remain their gene in future ages.

"You said, women have kept their lunch box in order to avoid robbing them for a long time haven't they?"

"It is just hypothesis based on the thought of "selfish gene", but do you think it is very persuasive?"

"I don't care robbing my lunch box by my friend at all!"

"It is a kind of miracle we can get and eat foods we want anytime over the last several ten years. It is a case that people who are in parts of this earth, are hard to live their life."

"Hmm, we are suffering from our gene as far as "lunch alone" is concerned.

"It might be just easy to understand if we think on such a way. But we should not run away toward the logic. It is a case that we have added to discrimination because of the existence of gene and sexual difference.

"To be continued"