​Since I study romantic relationships, I love it when friends, family, colleagues, or the random person sitting next to me on an airplane tell me about some New Fact About Relationships they read about in magazine, saw on TV, or heard from their grandparent and ask, "Is that true?!?". Better yet is when someone comes to me with Very Strong Feelings about what is good or bad for a relationship or whether their partner's behavior is reasonable, and I get to say, "Well, empirically speaking..." 

​Admittedly, the title of this post is kind of a straw man. Whether behavior genetic methods are appropriate for relationships research depends on what your question is.​And there are lots of potential questions one could ask. To list just a few:

1. Are there genetic influences on relationship outcomes?
2. Do relationship factors have a causal effect on some other aspect of individual functioning (e.g., the onset of alcohol use disorder or desistance from antisocial behavior)?
3. Do relationship factors moderate genetic influences on an outcome (e.g., are genetic influences on alcohol use attenuated for folks who are in relationships?)

I was going through some old files from graduate school the other day, and came across a paper that I wrote as a second-year graduate student in Matt McGue's "Behavioral Genetics" course. The paper, "Behavior Genetic Perspective on Marital Status: Divorce and Marriage" made me realize that I've been somewhat obsessed with the same question for a decade: Where do our thoughts, feelings, and behaviors in relationships come from?