Why Genetics Are Not Destiny (And Why That Matters for Healing)

(The Challenges of Interpreting Adoption and Twin Studies in Human Behavior)

This piece started as a school assignment.

I was asked to look at adoption and twin studies in one of my psychology classes, which meant revisiting the familiar nature versus nurture conversation. At first, I felt a little disconnected from it. I’ve seen this debate come up again and again, and it often gets flattened into simple conclusions that don’t really match what I see when I work with real people.

But the longer I sat with it, the more this assignment felt like an opportunity to notice something bigger. It wasn’t the research itself that felt off. It was the way genetic findings are often talked about, especially in healing and mental health spaces. The way we explain these ideas matters, because people don’t just hear information. They build beliefs about themselves from it.

When “it’s genetic” starts to feel limiting

In my work, I hear people explain their struggles through genetics all the time. Anxiety runs in the family. Sensitivity is inherited. Relationship patterns are just how they’re wired. Sometimes this explanation brings relief, especially for people who have spent years blaming themselves. But just as often, it carries a sense of resignation.

There is a shift that happens when someone starts to believe that their inner world is fixed by biology alone. They may stop wondering what could change. They may stop listening to their own experience. Hope becomes cautious, even if no one says that out loud.

That is where I tend to slow the conversation down.

Because genetics do play a role in human behavior, but genetics are not the whole story, and they’re not a life sentence.

What adoption and twin studies are actually meant to do

Adoption and twin studies are used to look at how genetics and environment both influence behavior. Identical twins share almost all of their genes, while fraternal twins share about half. When identical twins show similar traits, especially when raised in different homes, researchers often point to genetics as part of the explanation.

That information is useful. It helped psychology move away from the idea that environment alone explains everything. But the conclusions of these studies are often stretched further than they should be.

These studies talk about patterns across groups of people, not about individual lives. They do not tell us what is fixed about one person, or what someone will struggle with forever. They look at averages, not lived experience.

That distinction is easy to miss outside of academic settings, but it matters a lot when these ideas are applied to real people.

What these studies can’t really capture

Adoption and twin studies can’t measure emotional safety. They can’t measure what it feels like to grow up on edge, or how a child learns to stay alert in order to belong. They can’t measure the impact of inconsistent caregiving, chronic stress, or early relational wounds.

Even twins raised apart are still raised within environments that shape them deeply. Culture, family dynamics, financial stress, and emotional support all influence how genetic tendencies show up over time.

One idea that helped ground this for me came from behavioral geneticist Eric Turkheimer, who explains that genes always work within environments. Genetics don’t operate on their own. They are shaped by what someone lives through, especially early on.

Why this matters for healing

If genetics were destiny, healing would have clear limits. Growth would only go so far. But that is not what we see in real life, and it is not what research on the brain supports.

Brains change in response to experience. Nervous systems adapt when safety becomes available. Patterns that once helped someone survive can soften when the conditions that required them are no longer present.

This is why the way we talk about genetics matters. When people understand their patterns as responses to what they lived through, rather than flaws they were born with, something shifts: shame eases. Curiosity comes back online and change starts to feel possible again.

That doesn’t mean we should ignore biology.. it means it might not be helpful to view biology as a verdict.

Holding genetics with more care

What feels most accurate to me is this: genetics can influence sensitivity, temperament, and vulnerability, but environment and relationship shape how those tendencies unfold. Genes may set certain starting points, but they do not decide the whole path.

Two people can carry similar genetic risks and live very different lives depending on the support, safety, and meaning they experience along the way. That doesn’t weaken science; it makes it more honest and applicable for humans.

When we turn genetics into destiny, we lose nuance. When we allow space for both biology and lived experience, we end up with an understanding that actually matches what we see in human development.

Coming back to where this began

So yes, this reflection came from a school assignment about adoption and twin studies. But it led me back to something I already believe deeply:

People are not problems to be solved or data points to be explained away. They are shaped by timing, relationships, and experience, alongside biology. When we remember that, we stop asking what is wrong with someone and start asking what shaped them, and what might help now.

That shift matters: not just in theory, but in practice, especially for anyone working in healing, education, or caregiving.

References

Turkheimer, E. (2000). Three laws of behavior genetics and what they mean. Current Directions in Psychological Science, 9(5), 160–164. https://doi.org/10.1111/1467-8721.00084