I try to make as many of my important life decisions as possible based on the available scientific research. So, for example, one major reason I got married (beyond that my mother told me too :) ) was that married people are happier, richer, healthier, and have better sex lives.
Of course I try to make all my parenting decisions based on the same principle (though this is a lot more challenging because the research is often unclear).
Since I will probably want a second child, I was interested to read this paper on the spacing of births. I already knew that having a large family is a bad idea if you want quality children, but apparently having children too close in age (less than two years) also reduces academic achievement for the older child (presumably because parental investment is reduced, making them stupider). There are other bad effects of close spacing as well, including three times the risk of autism (for the second child), an increased risk of miscarriage/stillbirth/low birth weight, lower reading scores, and lower high school/college completion.
Although I didn't want closely spaced children before, this seals it: little R won't be getting a sibling until she's at least two and a half.
--Diet: Breakfast: Oatmeal with raspberry jam topping; Lunch: Peanut butter and jam sandwich; Dinner: Baked eggs and tomatoes, with noodles; Drinks: Frappucino, cocktail
--Other: did not drink 8 glasses water; one frappucino consumed