Sex dolls are more and more common these days, and, thanks to the rise in men, seemingly, falling in love with the silicon partners, less real humans are having sex and reproducing. At least, that’s the theory of experts in Japan, who, as a country, saw its birth rates fall below the one million mark last year.

In a new documentary called Substitutes — which focuses on the declining birth rates in Japan due to sex dolls — experts examine (and warn) that, due to loneliness, isolation and alienation, more men are turning away human relationships. In effect, it may be leading to the Japanese becoming an “endangered species.” Those are the words of the experts, not ours, so it’s a serious issue.

According to RT.com, sex doll industry leaders believe that as many as 2,000 lifelike sex dolls — complete with human characteristics and traits — are sold in Japan. With such popularity, it’s believed that more men in the country will even lose their virginity to these non-human beings, per a 2016 tweet from RT.com’s Twitter account.

Japanese sex dolls salesman Noburu Tanaka, who also owns one of the synthetic dolls that sell for $3,750, says that the increase in popularity could be attributed to lack of expectations that real-life women have, per RT.com.

“It’s an amazing feeling. It looks like a doll, but you feel as though it’s really alive,” he told RT. “When you make love to your wife, there can be some problems. With a doll, none of that matters.”

Although many people may chuckle at the idea of a declining population, as mentioned above, the issue is extremely serious, and poses a legit threat for a country, Japan, where the population is estimated to decline by a third in the next 30 years. That’s why Kanako Amano, a demography expert at the NLI Research Institute in Tokyo, says sex dolls pose such a threat.

“The biggest problem in Japan is the decline in birthrate and population. It’s being called a national disaster,” she said. “The Japanese are at a crossroads, facing the threat of extinction. We’re an endangered species.”

And, for those who think that it’s just men who are falling in love with these sex dolls, you’d be mistaken. At least, that’s the case with a young female named Hitsuji, who bucks the trend that sex dolls are only being used by older, lonely men. Here’s how she described her relationship with her doll, Masiro.

“Masiro is not a friend, a family member or a loved one. She’s a creature who accepts my love,” she said. “I have never consorted with men like that.”

With more and more men and women refusing to marry and find love elsewhere through sex dolls who meet their personal needs, the declining population and birth rates in Japan may be getting worse before they get better. Added Kanako Amano, “The curve of unmarried men and women is spiking up. This is the nation’s most accurate and trustworthy research.”

(H/T RT.com)