Dr Karl just gave us all a lesson in the science of love, lust and the decisions we make
Love StoriesShow Notes
What if your armpit smell, your birth control, and a dying octopus all had something to say about your love life? In this episode of Love Stories with beloved Dr Karl Kruszelnicki - Australia’s loudest shirt and sharpest science brain we pull apart the chemistry, hormones and fascinating questions behind who we want, why we stay, and when we should absolutely run alongside Deputy Editor of the Australian Women's Weekly, Tiffany Dunk.
We start with the body: menstrual cycles, the pill, and how shifting hormones can quietly reroute your attraction, your moods, and even how “into” your partner you feel. Then we go down the rabbit hole of smell - yes, your armpit funk and whether your odour is secretly swiping right on your behalf, nudging you toward someone whose immune system is a good match, or away from someone who suddenly just smells…not quite right for you.
From there, it gets even more real. We ask if your “butterflies” are actually your gut‑brain axis hitting the panic button, and how your fight or flight reflex can make you do objectively unhinged things in the name of “love”. Dr Karl advises "never have sex with someone who has more problems than you" : a thesis, a warning, and a t‑shirt. Moments you'll hear: We talk lust versus love the hot infatuation you feel in the early “honeymoon” haze versus the slower chemistry of long term attachment and how to tell whether you’re addicted to the drama, or actually building something with a new partner. What happens after you come out of honeymoon mode and realise you’re in a real relationship with a real human who leaves dishes in the sink? How do you keep going when the dopamine drops.
Along the way, Dr Karl brings one of the wildest animal stories you’ll ever hear: the octopus mother who quite literally self‑destructs after laying her eggs. Then we ask: what can human parents learn from this about burnout, personal 'tradeoffs', and the quiet ways our love for our kids evolves over time?
Because this is 2026, we can’t not go there: AI and modern love. People are not just flirting with chatbots anymore; they are forming real feeling relationships and emotional affairs with coding. We pull apart the psychology and neuroscience of why humans can bond so intensely with an always available, never arguing, perfectly attentive AI – and the big uncomfortable question: are we actually falling in love with AI, or with a mirror of ourselves?
All of it is filtered through Dr Karl’s signature true style as Australia's Favourite Science Dad - rigorous, effervescent scientific communication and our favourite thing on Love Stories: messy modern mysterious love. In this episode, we ask: Is your armpit smell helping you fall in love or warning you off? Can stopping the pill really change whether you fancy your partner? Why do you get butterflies in your stomach, and when should you ignore them? How does fight‑or‑flight make us do wild, sometimes self‑destructive things in relationships? Are you in love or in lust, and how do you tell the difference when you’re in deep? What actually keeps a relationship going after the honeymoon phase evaporates? What can an octopus’s hormone‑fuelled death spiral teach us about heartbreak and parental burnout? Can a mother not be genetically related to her child, and what does that do to our idea of “real” family? Can you really mend a broken heart, or do you just grow around it How does your love for your kids change as they grow and can science help you be kinder? Are we actually falling in love with AI, and what does that say about us?
If you’ve ever stayed with someone because the sex was great but everything else was chaos, wondered why your partner suddenly smells “off” when you come off the pill, or found yourself crying over a chatbot at 1am, this episode is for you. You’ll walk away with a new way to see love – as chemistry and choice, hormones and history....all stories you will absolutely tell at your next coffe catch up.
Thank yo
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