We avoided wheat only because it's one of the common allergens (soy, dairy, corn, wheat, nuts), and dd comes from a solid line of fairly allergic people. Some of the other grains out there are, I believe, more nutricious than wheat. Also, I find that wheat products tend to have a lot of questionable crap in them. That's the wheat avoidance rationale.
I try to balance dd's meals through the day to include a variety of foods, but mostly she eats what we eat with a few modifications. Ex: Breakfast yesterday was an egg yolk sprinkled with a little salt and pepper, a few segments of an orange, and a small handful of "popped" millet. Lunch was some leftover zucchini apple curry soup and a few more millet grains (they're handy for entertainment value while soup heats, or whatever. You can also get puffed kamut grains). Dinner was steamed broccoli with a bit of olive oil and some mixed beans. She also snacked on dates and a sippy cup of green smoothie. Often there's more fruit in a day, and I really rely on green smoothies for intake of greens as the only greens dd will really eat are broccoli and the occasional green bean.
There are two books that stick out in my mind as being good, and, of course, I have neither at hand as our stuff is all in storage right now. However, one was this one: http://www.amazon.com/New-Vegetarian...7773177&sr=8-1
It's a bit soy heavy for my tastes, but the grains and other information in it is really good.
The other one was, I think by Nina Plank. Something like this one: http://www.amazon.com/Real-Food-Moth...7773233&sr=1-1
I don't remember the fertility/pregnancy portion of the book, but it may have been there and just not relevant at the time. I really like her attitude towards food though.
The research I've read doesn't necessarily support delaying the introduction of certain foods. In fact, I've read studies supporting the idea that delayed introduction of nuts is a contributing factor in the development of allergies to same. However, I have seen a few studies that support delaying *when there is a significant history of allergies*. There's so much info out there, it can be a bit overwhelming, hey? My ultimate philosophy though is that if I'm eating well, and feeling well, then that's probably a good diet for my child to also follow.
Well, that was a bit of a detour from the quinoa!