'I have very little doubt that as we excavate the genetic matrix underlying the human body, we will discover that many faults and vices have a genetic origin. That violence, perhaps even spousal abuse, is genetically programmed into certain people and not into others. That alcoholism has a genetic basis. Even that innocent personality quirks, like the desire to be constantly chweing on something (a wad of tobacco, a stick of gum, a piece of paper) is coded into the sequence of amino acids that somehow adds up to you and me. Does this mean that we are therefore to live our lives constantly under the iron boot of genetic dictatorship? Not at all.
St. Paul told us this specifically: "For the desires of the flesh are against the Spirit, and the desires of the Spirit are against the flesh; for these are opposed to each other, to prevent you from doing what you would...And those who belong to Christ Jesus have crucified the flesh with its passiosn and desires." (Gal. 5:17.24).
Christ's crucifixion was a victory over the flesh; Christ, like very human being, had an inborn, genetically determined desire not to be tortured and put to death on a cross. He coudl have chosen to aviod it: both Caiaphas and Pilate gave Him ample opportunity to deny His divinity, declaim His Kingdom, and save His life. He did not. Why? Because there is something in a human being which is stronger than the genetic code.'
Melinda Selmys, Sexual Authenticity, p.65.