A short home video of two newborn girls lying side by side in a hospital cot has been watched millions of times because it looks like a conversation. One baby squeaks, the other answers with a coo, and the two seem to take turns. Are newborn twins really communicating? Not in words, and not with any message an adult could translate. But the clip touches on something real: twins are close to each other long before birth, and a well-known 2010 ultrasound study found that twin foetuses already make movements aimed at each other by the 14th week of pregnancy.
Below is what the video shows, what the research actually found, and what parents of twins can reasonably expect in the first weeks.
The video: two sisters taking turns
The clip, shared on YouTube in early 2022, shows the twins only hours old, wrapped up and lying close together. Each little sound seems to get a reply. Viewers loved the timing, and copies of the video were reported to have passed 15 million views across platforms, although that figure comes from viral reposts rather than one verified count.
Newborns make plenty of noises: grunts, sighs, squeaks and small cries, many of them reflexes linked to breathing, digestion and the change from the womb to open air. When two babies lie next to each other, those sounds can easily line up into what looks like a dialogue. That does not make the moment less touching. It just means the "talk" is our reading of it, not a translation.
What the 2010 twin study found
The research most often linked to this video is a paper titled "Wired to be social: the ontogeny of human interaction", published in PLoS ONE in October 2010. It was led by Umberto Castiello of the University of Padua, with colleagues from Turin, Parma (including the neuroscientist Vittorio Gallese) and the Burlo Garofolo children's hospital in Trieste. Older articles sometimes credit the study to Parma alone, but it was a joint project.
The team used four-dimensional ultrasound to film five pairs of twins in the womb, once at 14 weeks and again at 18 weeks of gestation. They sorted every movement by where it was directed: towards the wall of the uterus, towards the baby's own body, or towards the other twin. Even at 14 weeks, some movements were clearly aimed at the co-twin, and their share grew by 18 weeks.
The detail that caught attention was how those movements were made. Reaches towards the twin lasted longer and slowed down more gently at the end than reaches towards the uterine wall. They looked similar to the careful movements foetuses make towards their own eyes, the most delicate part of the body. The authors read this as a sign that the contact was planned, not accidental, and argued that humans may be "wired" for social behaviour earlier than had been assumed.
What the research does not show
It is worth keeping the study in proportion. Five pairs of twins is a very small sample, and not every recorded movement could be analysed. The paper is about touch and movement, not sound or language. It does not show that unborn twins talk, recognise each other in a conscious way, or that the girls in the video were continuing a conversation started in the womb.
A few common myths follow from stories like this one:
- "Twins have their own secret language from birth." Some twins do develop private words and sounds as toddlers, a pattern researchers call cryptophasia or idioglossia. By some estimates up to half of young twins have a shared language of this kind. It appears as children learn to speak and is generally seen as a passing stage that fades as their main language develops.
- "Twins always have a stronger bond than other siblings." Many twins describe an unusually close relationship, and growing up at exactly the same stage clearly plays a part. But closeness varies a great deal from pair to pair, and the womb studies cannot tell us how a bond will look at ten or forty.
- "The babies are telling each other something specific." Newborns do respond to voices, faces and touch, but meaningful turn-taking with sounds builds over months, not hours.
How babies really start to communicate
Babies are social from the very start, just not with words. In the first days they can see best at a distance of about 20 to 30 centimetres, roughly the distance to a parent's face during feeding, and they show a preference for faces and familiar voices. Crying is the main signal at first, and parents quickly learn that different cries can mean hunger, tiredness or discomfort.
Around six to eight weeks many babies begin to smile socially and to coo, making soft vowel sounds in reply to a smiling adult. Over the following months those exchanges become longer, babbling with consonants such as "ba" and "da" appears, and by around their first birthday many children say a first word. Every baby moves at their own pace, and twins born early may reach these steps a little later when counted from their birth date.
For twins, the "conversation partner" is sometimes the other baby. Parents often report that their twins watch each other, settle when placed close together for supervised awake time, or copy each other's sounds once babbling begins. These are lovely moments, and they are also good chances to talk back to each baby, which is what most supports early language.
Practical notes for parents of twins
Twin births are fairly common. In the United States, roughly three in every hundred babies born are twins (about 30 per 1,000 births in 2024, according to the CDC), and the rate rose for decades with older average maternal age and fertility treatment before levelling off. A few points come up again and again for new twin families:
- Talk to each baby by name. Twins share adult attention, so short one-to-one moments of talking, singing and reading help both.
- Expect them to be different. Even identical twins can differ in temperament, feeding and sleep. Comparing milestones too closely can cause needless worry.
- Ask about safe sleep. Hospital photos of twins together are common, but at home many paediatric bodies, including the American Academy of Pediatrics, advise that each baby has their own separate sleep space. Talk to your doctor, midwife or health visitor about the best set-up for your babies.
- Raise concerns early. If you are worried about hearing, feeding or how either baby is responding, talk to a doctor. It is always fine to ask.
Why the clip still matters
The appeal of the video is simple: two people who have shared every moment of their existence so far, still side by side, still reacting to each other. Science cannot say what the babies "meant". It can say that twins are physically aware of each other long before birth and that babies arrive ready to connect with the people around them. That is a good enough reason to watch the clip twice.
Sources: Castiello et al., "Wired to be social: the ontogeny of human interaction", PLoS ONE, 2010; University of Padua copy of the paper (PDF); DOAJ record of the study; CDC National Center for Health Statistics: multiple births; Wikipedia: Cryptophasia; video: YouTube.
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