Ok so I have been turning this around in my mind and I am going to just think out loud here and see what you guys think.
If you look at the table here
http://en.wikipedia.org/wiki/Testosterone (scroll down to the part where it says "Biosynthesis") you can see how your body manufactures these sex hormones, all made from cholesterol. Progesterone is among the first things to be made and then testosterone is made from some byproducts of that and then after testosterone is made, estrogen is made from the byproducts of the production of the testosterone. What if the l-arginine is somehow disrupting that and making your bodies produce more testosterone at the expense of the ingredients in the estrogen?? If it were, that would explain how it could both raise your testosterone and also dry you up.
It's very probable to me that most of the time on the blue diet, you're increasing your raw ingredients to such a point that there would be plenty of cholesterol to make both testosterone and estrogen. and I can also see how increasing testosterone in general could mean that there was plenty of by-products for estrogen. But maybe the l-arg is interfering in that, temporarily or in the longer term???
What I would do is if you are finding l-arg is drying you out, if you have many months before your sway, keep taking it and see if this reduction is temporary (the longer you are on the boy diet, the more raw materials you will have for producing BOTH T and E so it may be that you just need to wait out the sudden rise in T and your body will increase E production to make up the difference) IF you don't have a long time to go before your sway, stop the l-arg and you may even want to increase your egg intake for a few weeks to help give your bod enough cholesterol to make more estrogen with.
The good news is, this is very intriguing evidence in favor of l-arg being GREAT for DH to take. Something that may increase testosterone and reduce estrogen would be great for DH.
I do want to point out that we honestly don't KNOW whether or not we need high levels of both T and E to conceive a boy and also that we don't totally KNOW what is going on with the l-arg, but I just wanted to let you guys know what my thought processes were.