I first was informed of it around 15 years ago by a lecturer in a Child development class so I presume the theory has been around for some time and must be based on something. I'm fairly sure it was Erikson we were studying at the time so you could perhaps google him. Also try searching for serum Testosterone levels and see what you get. I know from my CBE training there are very high testosterone levels following birth the they drop off considerably (which is why infants up to two are fairly genderless except for the obvious physical differences) and start to pick up again in early childhood but not in significant levels until about age 9. It could be this 'start' of testosterone pick up Bidulph has capitalised on for his books.
Here I found one Chart, even though it doesn't start until age 6 you can clearly see the Testosterone has previously been on a high level and is on the drop.
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timeasmymeasure
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Date: 2006-10-21 01:27 am (UTC)It could be this 'start' of testosterone pick up Bidulph has capitalised on for his books.
Here I found one
Chart, even though it doesn't start until age 6 you can clearly see the Testosterone has previously been on a high level and is on the drop.