Recently a friend of mine who has a PdD in Botany and teaches as a university professor told me that peanut butter could cause cancer. A commonly known mold fungus aspergillus is known to grow in peanut butter and this mold releases toxic products called mycotoxins. The mycotoxin the aspergillus produces is called aflatoxin which is documented to be a highly carcinogenic chemical and is one of the most well known documented carcinogenic agents.
I was told almond butter is a much better choice and I do no have to worry about it being contaminated with mycotoxins such as aflatoxin as it occasionally happens peanut butter. My friend actually said that this fungus grows in organic butter a lot easier since there are not many pesticides so he said trying to get organic peanut butter won't solve the problem but may make it much worse.
Another thing my friend pointed out that peanut butter machines in health food stores such as wholefoods are a perfect environment for the aspergillus mold to grow so it is very important that these machines are cleaned daily.
This is something I do not plan to risk so I highly recommend you do your own research on this before you make your own decision for yourself and for your family.