Babies born prematurely could face unexpected long-term impacts to their love lives.
A study of more than 4 million people has found preterm or underweight babies are less likely to grow up to have sexual or romantic relationships.
Scientists say this may lead to a lower sense of wellbeing and poorer physical and mental health.
"These associations were found for both men and women, and were stronger the lower gestational age," University of Warwick researcher Marina Mendonca told Newsweek.
"This means that the chances of finding a romantic partner or having children were lower for those born very or extremely preterm, with the extremely preterm born adults being for example 3.2 times less likely to ever have sexual relations when compared to their full-term peers."
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As they get older, their chances don't improve - with no difference in romantic and sexual success between 18- and 25-year-olds.
Preterm children were 22 percent less likely to grow up and have kids of thier own, and 57 percent more likely to stay a virgin their entire lives.
"Previous studies had suggested that people born preterm could take longer to make social transitions normative of adult life, such as a romantic partnership and parenthood," said Mendonca.
"Rather than a delay, our findings suggest persistent difficulties in making these social transitions, which have been associated with negative outcomes later in life, such as lower wealth, social isolation, and poorer physical and mental health."
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Mendonca said previous studies have found people born preterm tend to be shy and take less risks, but more research is needed to find out if this is why they're unlucky in love.
She said improvements in infant care in recent decades may see the gap between preterm and full-term kids narrow in the future.