A 10-year-old boy who is accused of impregnating a girl, 13, is too sexually immature to have produced sperm, says a leading doctor who examined him.
But the girl has insisted she had no other partner, a claim believed by an expert psychological profiler.
With parental permission, a troubling television show revealed the faces of the children at the centre of a case that has caused deep controversy and concern in Russia.
The boy and his parents agreed to his medical examination and the results were revealed to millions of viewers when the children, Ivan and Darya, were out of the studio.
Despite widespread reports that he got her pregnant, the popular On Air Live show with presenter Andrey Malakhov highlighted Dr Evgeny Grekov, an urology and andrology expert, who denied Ivan could be the father.
"We rechecked the laboratory results three times so there cannot be any mistake,” he told viewers.
“There cannot be sperm cells. He is still a child.”
Ivan has barely started adrenarche – the early stage of sexual maturation, Dr Grekov said.
“There is even no testosterone. And just to add, he still has childish sex organs.
“Puberty has not started. So we have a lot of questions.”
The Rossiya 1 channel show – titled ‘Father at 10!?’ - highlighted a neighbour in Zheleznogorsk, a nuclear production city in Siberia which is closed to outsiders, suggesting the girl had an older partner.
“Obviously, someone else did this. They just want to hang it on the boy now,” the male neighbour in his 40s said.
But the 13-year-old girl Darya denied this and told viewers: "It was Vanya's idea [to have sex].”
“But I did not mind. He closed the door, leaving the key in the lock, so his mum could not open the door.
“It was scary a bit, that it would be painful. It was just a little - and then everything was normal.
“It was a bit shameful, we were just hiding under the blanket.
“I did not think that aged 10 he can do such things... I thought that nothing would happen.”
Psychologist Denis Davydov said when Darya was interrogated on whether she had sex with anyone else, she gave a “sharp rejection”.
“This gives me the right to say that she had no contacts with other boys or men, she only had Vanya as a partner,” he claimed.
The boy – who gave her roses when they started dating in February – was asked by famous Russian presenter Andrey Malakhov that “when [he] kissed Dasha and so on, that it could lead to such consequences?”
“I did not think about this,” he replied.
When asked if the child could be someone else’s, the boy said: “This cannot be.”
The girl and her mother want to keep the baby but it is too early in the pregnancy for a DNA check on the child, which will be completed later.
“She confessed that she was with Vanya…and had a good time once,” Darya’s mother Elena, 35, said.
“I cannot understand how this could be? Just wake me up, I cannot believe it.”
The boy’s mother Galina is convinced he is telling the truth.
“I believe to my son. That he is the father. I understand that he himself maybe doesn't realise what happened.
“He is just a child, no matter if he feels himself older.
“He told me that they came to our flat, Dasha suggested it, and they had [sex] only once.”
During the show, Darya asked him in a low voice: "Are you scared?”
“Very,” he replied.
“No worries,” she told him.
The boy and girl attend different schools.
The Russian Investigative Committee has begun a preliminary check into the case.
Do you have a story tip? Email: email@example.com.