Male vs Female Dogs: Do Temperament Differences Matter

By Jessica Ennis, DVM, CVA

Breed care · August 5, 2026 · 5 min read

The sex on the intake form tells you less about the dog you'll live with than almost anything else on that form.

Before the breed name, before the coat color, run this checklist first — it predicts more than “boy or girl” ever will:

• Energy and exercise needs relative to your household’s actual schedule
• Bite and resource-guarding history in the individual dog, not the sex
• Spay/neuter status and age at the procedure, since hormones shift some behaviors
• How the dog was raised and socialized in the first 16 weeks
• Whether you already have another dog, and that dog’s sex and temperament
• Individual variation within the litter — littermates of the same sex can differ wildly

Owners ask me constantly whether they should get a male or a female, usually because a friend swore one sex was “calmer” or “more loyal.” I understand the instinct. It feels like useful information. In my experience it is one of the least useful questions an owner can ask, and I want to walk through why before we get to what actually matters.

The disputed premise: does sex really predict temperament?

The honest answer, grounded in the evidence, is: less than most owners assume. A frequently cited overview in PLOS ONE / PMC: PLOS ONE on behavioral and perceptual differences between sexes in dogs found real but modest patterns — males tend toward more social play and can be more distractible, while females often show more cooperative behavior with people and more focused attention in confined spaces. Those are population-level tendencies, not rules for any one dog.

On aggression specifically, the picture gets murkier, not clearer. A study on PMC: Aggression toward Familiar People, Strangers, and Conspecifics in Gonadectomized and Intact Dogs found that reproductive status and the circumstances around it shaped aggressive tendencies more consistently than sex alone did — and some findings ran counter to the popular assumption that intact males are automatically the highest-risk group.

I want to be direct about where I land: sex is a minor input, not a planning tool. If you’re choosing a dog based mainly on “boy dogs are goofier” or “girl dogs are more independent,” you’re optimizing for a variable that barely moves the needle. The strongest counterargument I hear is that breeders and rescue staff repeat these generalizations constantly, so there must be something to them. There’s a kernel — average differences in play style and attention do show up in research — but “average difference across a population” is not the same as “predictive for the individual dog in your living room.” I still land on temperament testing the actual dog over trusting a sex-based label, and the American Kennel Club has made a similar point about how much of this is projection rather than measured behavior.

What actually does shift behavior

A few dogs stand out in my memory because the owners had done real homework on sex and still got surprised by what actually changed the dog’s day-to-day disposition. One was a 3-year-old female Labrador, spayed at five months, who I saw for a wellness visit after her owner mentioned she’d become noticeably more reactive to strangers approaching the porch — something that had started gradually over about eight months, worse in the evenings when the neighborhood dog-walking traffic picked up. The owner had chosen a female specifically because she’d read females were “calmer with strangers.” What we worked through instead was early spay timing, a stretch of under-socialization during a move when the dog was seven months old, and a porch layout that gave visitors a straight sightline to the front door with no buffer. None of that had anything to do with sex. Once we addressed the environment — a visual barrier, a settle-on-mat routine before the doorbell — the reactivity dropped within a few weeks. That case is the one I come back to when an owner tells me they’re picking a sex to avoid a behavior problem.

Reproductive status matters more than sex itself, and the timing of spay or neuter matters more still. According to American Veterinary Medical Association: AVMA gonadectomy resources, sterilization removes hormone-driven behaviors like roaming, marking, and mounting, but it does not rewrite a dog’s core temperament. That’s an important distinction for owners to hold onto: you can expect certain hormone-linked behaviors to fade after the procedure, but you should not expect a fundamentally different personality to emerge.

Socialization window, genetics from the specific parents, and the home environment carry far more weight than sex. A shy litter tends to produce shy puppies of both sexes. A confident, well-socialized litter tends to produce confident puppies of both sexes. If you’re choosing between two puppies from the same litter, the sex distinction is close to noise compared to watching how each pup handles novelty, recovers from a startle, and engages with your hands and voice during a short supervised visit.

Where multi-dog households change the calculus

This is the one place sex genuinely earns a spot on your checklist: household composition. If you already own a dog, same-sex pairings — particularly female-female — have shown up in behavioral case series as more likely to escalate into serious household conflict than mixed-sex pairings, though this is a tendency, not a certainty, and plenty of same-sex households do fine. If you’re adding a second dog, I’d rather you spend your planning energy here than on picking the “right” sex for a solo dog. Introduce slowly, on neutral territory, and watch body language over several sessions before committing.

For breed-specific mobility and airway considerations that matter more than sex when you’re comparing two candidates, see our French Bulldog vs Boston Terrier comparison, and if you’re weighing energy needs against your living situation, our guide to apartment-friendly breeds walks through what actually predicts a good fit.

In my practice, the owners who end up happiest are the ones who stopped asking “male or female” and started asking “what does this specific dog need from me.” I’ve sat with families choosing between two puppies — same litter, same breed, three weeks apart in age — where the deciding factor ended up being which puppy approached the toddler calmly and which one bolted for the door. Sex never entered the conversation again after that visit. That’s the shift I try to walk every new owner through: replace a demographic guess with five minutes of watching the actual animal.

An owner’s decision checklist

• Meet the individual dog before deciding anything based on sex
• Ask about the litter’s overall temperament, not just this puppy’s sex
• Confirm spay/neuter status and, if unaltered, discuss timing with your vet
• If adding a second dog, weigh same-sex vs. mixed-sex pairing dynamics seriously
• Prioritize documented behavior history over a stranger’s generalization
• Revisit training and socialization gaps before assuming sex explains a behavior change

For breeds where exercise tolerance and structure matter as much as personality, our Border Collie vs Australian Shepherd piece and German Shepherd vs Belgian Malinois comparison go through what actually differs — and it’s rarely sex.

So did the temperament differences turn out to matter as much as the intake-form question implies? Not in my experience, and not in the research I trust. What would it take to convince you otherwise the next time someone tells you “boys are just more chill”?