I've seen so much conflicting information on caffeine that I really don't even pay attention, anymore.
I drink two mugs of coffee a day (and very rarely - a few times a year - I drink three or four). I've been doing that since I've been a SAHM. (I used to drink more than that fairly regularly when I worked in an office.) I drink it when I'm pregnant and when I'm breastfeeding, and when I'm neither...to the best of my recollection.
I've never noticed any ill effects for me or my kids. I do have intermittent sleep issues, but the only relationship between them and my caffeine intake is that if I slip up and have a bunch of caffeine late in the day, it will keep me up. That hasn't happened in a long time, probably because it was usually a Coke at a movie or something, and I haven't been to an evening movie in years.
If I can't have coffee one day, I get upset, because I love the taste and smell and the whole morning ritual - but I don't get withdrawal headaches or anything like that. I've never noted any ill effects on any of my kids, either.
Caffeine is basically something that I've made up my mind not to worry about, anymore. Coffee (and some dark chocolate) plays a positive role in my life, and I simply see no evidence that it's causing me any negative health effects. My mom, who is a lifelong coffee drinker, in greater amounts than me, also shows no signs of any health issues, and she's 66.