Beginning in the 1980’s and continuing until the present time, research studies on identical twins have found ways to measure how commonly “heritable” various personality traits can be. After comparing large numbers of identical and fraternal twins, one study statistically determined, for example, that happiness is an 80% inherited trait (Colt). As another source described it, these twin studies have “found the invisible hand of genetic influence helping to shape our lives” (Peter Miller, National Geographic, 2012).
And, for me, these genetic codes that impact our personality also determine something else. They explain why higher levels of moral goodness are not something that we can will ourselves into. While most of us can stop ourselves from robbing banks or clubbing someone over the head, giving without judgment or loving without conditions can be largely impossible. We may hear that inner voice, the one that is telling us what God intends us to do. But “genetic influence” can interfere with our obedience. St. Paul, for example, described himself as “the worst” of sinners, “a blasphemer and a persecutor and a violent man” (NIV 1 Tim. 1:13-16). And many of us would probably add pride or arrogance to his list of faults! But Paul explains his successful discipleship by saying, “the grace of our Lord was poured out on me abundantly.”
And we need that abundant grace poured out on us as well. Only the spirit of the Lord moving in our hearts makes true and lasting Christian charity possible. If we think we can always be unselfish and unconditionally kind out of our own strength of character and personality, we’re going to fail. So we need to be very grateful, as Paul was, for the Lord’s grace and “immense patience” (NIV 1 Tim. 1:16).
(George Howe Colt, “Were you born that way?”1998. Peter Miller, National Geographic, 2012) (first written in Living Large, chapter 59)