When exactly you lose your virginity has been thought of as a fairly random event, dictated by chance and circumstance.
But now an international team of scientists, led by the University of Oxford, reveal the milestone is more controlled by our genetics than we may realise.
They say they’ve identified 371 regions of our genetic code that appear to influence not only when exactly we first have sex, but also when we have our first child – not just for women, but men too.
Their analysis of Brits’ data revealed genetics can explain between five and 17 per cent of when individuals achieve these two milestones.
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An Oxford-led team discovered hundreds of genetic markers driving two of life’s most momentous milestones – the age at which people first have sex and become parents
MEAN AGE OF FIRST SEX BY COUNTRY
– Brazil 17.3
– New Zealand 17.5
– Germany 17.8
– UK 18.3
– US 18.4
– Canada 18.5
– France 18.7
– Ireland 18.7
– Mexico 19.1
– Spain 19.5
– Japan 20.4
– China 21.2
– India 22.5
– Malaysia 23.7
Source: Durex (2016)
The study has been led by Professor Melinda Mills at the Leverhulme Centre for Demographic Science, the University of Oxford.
‘Our study has discovered hundreds additional genetic markers that shape this most fundamental part of our lives and have the potential for deeper understanding of infertility, later life disease and longevity,’ she said.
‘Age at first sexual intercourse and age at first birth have implications for health and evolutionary fitness.
‘We anticipate that our results will address important interventions in infertility, teenage sexual and mental health.’
The study, published in Nature Human Behaviour, used data on age at first sexual intercourse (AFS) and age at first birth (AFB) – how old a woman is when they have their first baby.
For AFS, the team included 397,338 pooled individuals (214,547 women and 182,791 men) from the UK Biobank – a database containing in-depth genetic and health information from half a million UK participants.
For AFB, researchers included 542,901 individuals (418,758 women and 124,008 men) from 36 previous studies.
The team linked 371 specific areas of our DNA, called ‘genetic variants’ (known locations on chromosomes, in other words) to the timing of first sex and birth.
In all, there were 282 genetic variants linked to AFS and 89 linked to AFB.
This is hundreds more than the previous studies that found 38 for AFS and just 10 for AFB.
Professor Mills told MailOnline that is is not genetics or social environment alone that dictate AFS and AFB, but rather an ‘interaction of both nature and nurture’.
‘We knew that the timing of what we call “reproductive onset” – age at first sexual intercourse and child – is largely related to and predicted by social and environmental factors, like obtaining higher education and availability of contraception,’ she said.
‘What this study does is extend what we know about the social and genetic predictors to find not only the proportion explained by genetics, but isolate actually the genetic variants (location on your DNA) and examine their biological function.’
Surprisingly, the influence of genes on when women have their first child appears to have increased over the years, the study found.
2019 research suggests a substantial proportion of young people in Britain are not ready for their first sexual activity (stock image)
Genes had a bigger influence over time of first birth for women born in 1965 (22 per cent) than for women born in 1940 (nine per cent).
Some of the areas of DNA they identified are thought to be linked to reproductive functions, while others are linked to our behaviour, they say.
Genetics underlying early sex and fertility were related to behavioural disinhibition, the team found, like ADHD, addiction and early smoking.
Meanwhile, those genetically prone to postpone sex or first birth had better later life health outcomes and longevity.
Having a first child later in life was linked with living longer and being free of type 2 diabetes and heart disease.
‘We demonstrated that it is a combination of genetics, social predictors and the environment that drives early or late reproductive onset,’ Professor Mills said.
‘It is exciting that the genetics underlying these reproductive behaviours may help us understand later life disease.’
According to Durex, the average age for people in the UK to lose their virginity is when they’re 18.3 years old – well over the legal age of 16.
According to another 2018 study, the number of young people in Britain who have never had sex is on the rise.
One in eight 26-year-olds told researchers at the Next Steps project – which charts the private lives of millennials – that they were virgins.
Factors accounting for having sex later included a fear of intimacy and being humiliated on social media, the study found.
When young Brits do have sex for the first time, many were not ready for it, according to research published in 2019.
YOUNG PEOPLE IN BRITAIN ‘ARE NOT READY DURING THEIR FIRST SEXUAL ENCOUNTER’
Young Brits are not ready when they have their first sexual encounter, a 2019 study published in the BMJ Sexual & Reproductive Health revealed.
They also lose their virginity under circumstances that are incompatible with positive sexual health, the study authors, from the London School of Hygiene & Tropical Medicine (LSHTM), said.
The experts used data from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3), one of the largest scientific studies of sexual health and lifestyles in Britain.
In the study 2,825 sexually experienced 17 to 24-year olds were asked about their experience of losing their virginity.
The questions aimed to gauge their level of ‘sexual competence’, defined as consent, autonomy, contraceptive use and readiness.
Only respondents who answered yes to all four domains were deemed sexually competent.
Just under 52 per cent of all the female respondents and 43.5 per cent of all the male respondents weren’t deemed sexually competent.
Analysis of the responses showed that nearly four out of 10 women (just under 40 per cent) and around one in four men (26.5 per cent) didn’t feel that their first sexual experience had happened ‘at the right time’.
Almost one in five women said that they and their partner had not been equally willing to have sex on the first encounter
A similar proportion of women reporting that they had not been in charge of the decision to have sex for the first time.
‘Age is often used as a determinant of readiness for sex,’ said study author Kaye Wellings at LSHTM at the time.
‘The problem with this measure is it assumes every young person is the same, that they will all wake up on their sixteenth birthday equipped with the qualities that will enable them to have safe and satisfying sexual experiences.
‘Our findings show this isn’t the case. Every young person is different – some 15 year olds may be ready while some 18 year olds are not.’