A parasite, (Toxoplasma gondii) infects the brain of rats and mice and changes they’re behavior by making them drawn to, rather than fearful of, the scent of cats. This effect is obviously disastrous for the rat but advantageous to the parasite, which will be able to sexually reproduce if its host is eaten by a cat. The infection is highly precise, as it doesn’t affect a rat's other fears such as the fear of open spaces or of unfamiliar smelling food.

A religious equivalent, for Christianity in this case, is the story that a man executed 2,000 years ago can take away responsibility for an individual’s socially unacceptable behavior. Accepting the parasitic meme that a supernatural entity has the capability of ‘forgiveness’ provides stress relief or even elation after immoral actions.

This is primarily advantageous to the religious parasitic meme in this case Christianity, as it will replicate from that individuals brain to other people, specifically that person’s family.

On first observation, it’s also advantageous to the individual as well. However, the impact to that individual in the long run, a wasted life in the service of a delusion, is unfortunate to say the least, but the impact on that individual’s society could be devastating. The damage from the Christian meme today ranges from refusing a woman’s right to choose, discrimination against homosexuals, to the murder of abortion doctors. The damage from the Christian meme today ranges from refusing a woman’s right to choose, discrimination against homosexuals, to the murder of abortion doctors.

In the past it was justification for the Crusades, the Conquistadors, slavery, and the persecution of those advocating scientific advancement, continued today in the case of evolution, stem cell research, etc.