I am not qualified to give a science lesson on BPA and nor do I think you want one. So to put it simply, BPA is a chemical used to create hard plastics. It mimics estrogen and creates reproductive mutations in the womb. It is linked to heart disease, reproductive issues, low sperm count, increased risk of breast and prostate cancer, among other issues. Canada has declared it a toxic substance.
Yes, there are studies out there that attempt to discredit the science that BPA is harmful. I have three things to say about that. First, who sponsors those studies? Second, I live in Los Angeles, where I have no choice but to breathe toxic and polluted air, so why not decrease the ingestion of chemicals where I can. Third (and probably most important), if the science is "inconclusive," I refuse to be a lab rat and will not allow my son to be one. So here's my solution to the BPA issue:
The lining of canned foods is made with BPA and it has been proven that the BPA leaches into the food, so canned vegetables are a thing of the past. We try to eat fresh vegetables mostly, but I also have a stock of frozen veggies in the freezer. Whole Foods' frozen veggies come in BPA-free plastic bags. I would love to say that we cook our beans from scratch but, really, who has the time? I only buy Eden Organics canned beans, where the cans are not only BPA-free but there is no sodium added so we control the salt content (there are other organic brands with BPA-free cans, but we love Eden Organics so we're sticking to it). There is no such thing as BPA-free canned tomatoes. But I stumbled upon Pomi Tomotoes, which comes in BPA-free cardboard boxes. While it is not organic, it is grown in the hills of Italy according to the EU's organic standards. And the only ingredient is tomatoes (have you ever looked at the ingredients of Hunt's canned tomatoes? Might surprise you that tomatoes is but one of 9 ingredients, and there are 980 mg of sodium in one can; by comparison, Pomi has one ingredient - tomatoes - and 60 mg of sodium in the whole box). I buy Pomi in bulk on vitacost.com.
I avoid any plastic with the #7 recycling code on it because that is most likely to contain BPA. I still have BPA-free plastic tupperware in my house but we rarely use it because BPA-free plastics have also been found to leach toxic, endocrine-disrupting chemicals. I use glass storage for almost everything. For my son, stainless steel or silicon. We use Lunchbots for lunches and Kids Konserve Nesting Trio for snacks and stainless steel water bottles for water when we're out of the house. I have used the Kinderville products since the puree stage - the big and small storage containers are fantastic for snacks, plates are great for meals, and the cups are great for - I'm guessing you can figure out what they're great for. They can be safely heated, too. I would also recommend Dandelion products. I have not used them so cannot vouch for them (I already invested in the above and did not need anything more) but the products are made from corn. Thank you, innovative company, for making the overabundance of corn in the US into something fantastic (ie, a non-toxic plastic substitute) instead of something disease-inducing (ie, high fructose corn syrup).
Even if you continue to use your plastics, just keep in mind that BPA and other harmful chemicals tend to leach when exposed to high heat, so don't microwave in plastic containers ever (microwave safe does not mean that it is safe for you; only that the plastic won't melt) and don't wash plastics in the dishwasher (this alone is reason enough to invest in good glass storage containers).
This was a pic from a while ago. It's of my son enjoying my grandma's food in his Kinderville plate (yes, I took the plate to Israel with me on a visit to see my grandma cuz he was too young for glass plates, I didn't want him to eat on plastic, and I'm neurotic like that).