"PhysOrg reports on a study by Robert Rowthorn, emeritus professor at Cambridge University"
Note he's an Emeritus professor of economics
, not any scientific discipline. Note also he's a former editor of Black Dwarf and a self confessed radical Marxist who enjoys controversy.
Rowthorn says that while fertility is determined by culture, an individual's predisposition toward religion is likely to be influenced by genetics, in addition to their upbringing.
Think about this. In plain English, he's saying the number of children an individual has is influenced by culture rather than genetics, while religion is a genetic rather than cultural phenomena.
In the model, Rowthorn uses a "religiosity gene" to represent the various genetic factors that combine to genetically predispose a person toward religion, whether remaining religious from youth or converting to religion from a secular upbringing.
In other words, he's taking cultural ideas and treating them like gene's. There's no actual genetic influences which would make one susceptible to religion, beyond perhaps an over-active imagination.
tl;dr - You got troll'd.