Tim Tyler,

Genes and memes are both things on which evolution acts (replicators), but they also have important differences so it's useful to use different words. In particular, the logic of *what sort of behaviors would evolve in people* is different if you consider memes or genes. The available replication strategies are different if for genes (which require sex and parenting) and memes (which require older people to communicate to younger people).

Whether something is genetic or memetic is also highly relevant to A) *how* (by what mechanism) it might influence people's behavior B) how difficulty it is for someone to change that trait.