I think that's a bit biased - some men seem to be more ambitious/successful; the environment is brutal to men to compete with each other, often for scraps. There also seems to be way more men at the bottom of the pyramid, homeless ones, losers of evolutionary selection. Maybe we should start talking about them as well?
As why many girls make that "decision" at around 12 - they might be smarter and see that they don't have to work that much anymore. Maybe in the past when things like cooking for 10 people family or washing clothes/cleaning were super difficult the partners had to form a team; these days most of this is semi-automated and allows different strategies.
Do you really believe that girls aren't making conscious choice to stay away from "weird smelly" engineers in STEM fields that are now popular wrt. $/status but were completely undesirable 20 years ago? Have you grown up completely isolated from young females and couldn't observe what were their choices? Yes, I have seen a lot of men dissing them "just females, can't be good" (I hated it in my idealistic youth), but then later you observe their choices and they aren't doing themselves any favors either, usually picking "safe choices" instead of risky ones needed for success.
My comment was in response to your initial point that "“Many girls decide at around age 12 ... to get a husband that will do all the heavy lifting". I don't think it's because they're "smarter" because in the long run it costs them opportunity, power, wealth, etc that people in the workforce acquire over time. There might be an element related to a partnership at home, but as Sandberg points out in Lean In, this should affect women's decisions in their 30s, not their decisions about their college major when they're 18.
I'm a female founder who majored in CS and left my PM job at Google to start a company, so I have "observed the choices" of many young females considering engineering. It's not enough to say that "women are just choosing the wrong thing" - we need to find the underlying cause of those choices if we want to shift the demographics.
- I can't take Sheryl seriously; she's not a prototype of a woman that risks a lot to achieve success and her dating advices IMO just poison the well to most regular women, as not many men contemplating serious relationship want to have anything with women following her advices
- from my personal experience of running multiple companies, I once offered significant equity in an e-commerce startup to a woman as one of two founders. Her reaction was that once the company nets $1M, I can give her 50% stake. This risk aversion is the norm. I have only one counter-example of a female CFO that was driven to succeed against all odds.
- young males are now seriously disadvantaged; they have to be like 50% better than females to even get to interview stage in most lucrative tech companies. This is obviously not sustainable nor fair and a backlash is mounting. Either they completely drop out of society, or become associated with extremist male-only movements. This is very troubling and a waste of potential.
As why many girls make that "decision" at around 12 - they might be smarter and see that they don't have to work that much anymore. Maybe in the past when things like cooking for 10 people family or washing clothes/cleaning were super difficult the partners had to form a team; these days most of this is semi-automated and allows different strategies.
Do you really believe that girls aren't making conscious choice to stay away from "weird smelly" engineers in STEM fields that are now popular wrt. $/status but were completely undesirable 20 years ago? Have you grown up completely isolated from young females and couldn't observe what were their choices? Yes, I have seen a lot of men dissing them "just females, can't be good" (I hated it in my idealistic youth), but then later you observe their choices and they aren't doing themselves any favors either, usually picking "safe choices" instead of risky ones needed for success.