Why Do Siblings Often Resemble One Parent More Than the Other?
That exact question has sparked a widely shared thread on Quora, filled with curious, heartwarming, and sometimes humorous stories, each exploring why one sibling might resemble Mom. At the same time, another is a spitting image of Dad.
The answer lies in the fascinating randomness of genetics. Siblings share about 50% of their DNA, but that doesn’t mean they inherit the same combination from each parent. During the formation of eggs and sperm, chromosomes undergo a process called crossover, shuffling genetic material in brand-new ways. This means sibling A might inherit Dad’s curly hair gene, while sibling B gets Mom’s straight locks, and both may get different mixes for every trait.
Beyond genetics, environmental and developmental factors—such as nutrition or epigenetic influences—can slightly alter traits over time. Think of nature and nurture as partners in determining how siblings manifest their features.
The result? Families often present this intriguing visual puzzle: one kid resembles Grandma, another rocks Grandpa’s nose—but each remains uniquely themselves because of that genetic shuffle and personal life experiences. As one person on Reddit summed it up:
“A child can look very much like one parent while one sibling looks very much like the other parent…” reddit.com
What’s Your Take?
It’s fascinating how siblings paint different portraits of the same family canvas. Has your household ever experienced this marvel of resemblance? Are the differences purely cosmetic, or have they sparked conversations, nicknames, or even sibling rivalry? Genetics may set the stage, but your stories bring it alive. Share below how your family’s genetic lottery unfolded—and what it taught you about identity, heredity, and the joy of watching kids grow into their faces.
Related Blog posts
The Starglow Parenting Weekly
Your shortcut to purposeful parenting.
Join thousands of thoughtful parents who get our weekly roundup of tips on screen time, mindful discipline, and finding balance—delivered every Sunday morning.