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Nearly a third of Japanese people are entering their 30s without any sexual experience, according to research.
The country is facing a steep population decline as a growing number of youngsters abstain from sex and avoid romantic relationships.
Some men claimed they "find women scary" as a poll found that around 31% of people aged 18 to 34 from the island nation say they are virgins.
One woman, when asked why they think 64 per cent of people in the same age group are not in relationships, said she thought men "cannot be bothered" to ask the opposite sex on dates because it was easier to watch internet porn.
The number of births dropped below one million in Japan for the first time last year, according to the Ministry of Health, Labour and Welfare.
Japan's National Institute of Population and Social Security Research predicts that the country's current population of 127 million will decline by nearly 40 million by 2065.
The fertility crisis has left politicians scratching their heads as to why youngsters are not having more sex.
Comedian Ano Matsui, 26, told the BBC: "I don't have self-confidence. I was never popular among the girls.
"Once I asked a girl out but she said no. That traumatised me.
"There are a lot of men like me who find women scary.
"We are afraid of being rejected. So we spend time doing hobbies like animation.
"I hate myself, but there is nothing I can do about it."
Artist Megumi Igarashi, 45, who once made a 3D image of her own vagina, said "building a relationship is not easy".
"A boy has to start from asking a girl on a date," she told the BBC.
"I think a lot of men just cannot be bothered.
"They can watch porn on the internet and get sexual satisfaction that way."
The shrinking of the country’s population – deaths have outpaced births for several years – has been called a "demographic time bomb" and is already affecting the job and housing markets, consumer spending and long-term investment plans at businesses.
Other countries including the US, China, Denmark and Singapore have low fertility rates, but Japan's is thought to be the worst.
A nationwide survey earlier this year revealed that nearly a quarter of Japanese men at the age of 50 are yet to marry.
The report, from the National Institute of Population and Social Security Research, also found one in seven Japanese women aged 50 were yet to be married.
Both figures were the highest since the census began in 1920, and represent a raise of 3.2 per cent among men and 3.4 per cent among women from the previous survey in 2010.
The growing trend was attributed to less social pressure to marry as well as financial worries.
The institute said the number of single Japanese people will likely rise, as another survey shows more young people have no intention of getting married in the future.