Two leaders in the field of memetics are Henry Plotkin and Richard Dawkins. They both agree that memes differ from genes in at least one major way: Memes do not replicate physically, and therefore they subject themselves to the possibility of imperfect replication. As Dawkins puts it, "It looks as though meme transmission is subject to continuous mutation, and also to blending." Plotkin writes, "Memes, however, may blend. It is at least reasonable to consider that cultural inheritance may, under some circumstances, result in blending, especially as, unlike genes in sexual reproduction, memes may be inherited from multiple sources." Plotkin and Dawkins both use the example of the God meme. Plotkin says that we hear about God from various sources such as family, school, the media, friends, and acquaintances. Not all these sources will transmit the exact same information about God. There will be various disparities between these God stories… Both Plotkin and Dawkins call this blending.