I offer no statistical evidence to support my assertion. ALl I can forward is a logical argument. Since there is no causal link between marriage and the frewquency with which couples engage in oral and/or anal sex, I see no reason why the presence or absence of marriage should have any impact on that activity. (In fact, it is arguable that, given the availability of a presumably willing partner, the fequency of such acts actually increases in married couples.)
My dictionary defines "specious" as "superficially logical but fundamentally flawed." I stand by my usage.
Then supply the fundament.