School children who want to change sex are risking their lives by buying illegal hormone drugs online.

A Mail on Sunday investigation found that increasing numbers of boys under 16 are obtaining prescription-only oestrogen with frightening ease.

They opt for the hormone because it hinders hair growth, induces breast development and reduces muscle mass. But it can cause sexual dysfunction, type 2 diabetes and incontinence, and their effects can be irreversible. They also carry the risk of causing infertility and depression.

Bertie Heaver, 15, purchased 28 oestrogen pills without a prescription from an online pharmacy as part of our investigation (with his parents' permission). He is not transitioning

Teenagers have been using internet forums to discuss how to get sex change drugs

Girls wishing to change gender often opt for testosterone, as it encourages facial hair growth, deepens the voice and makes them more muscular but it carries the risk they could develop cardiovascular disease and cancer. It is more difficult to acquire testosterone online – but doctors fear many girls obtain it on the black market.

Normally, young people considering changing sex are referred to gender identity clinics where they are rigorously assessed, and given hormone drugs under supervision only if they are over 16.

But we found that one company, Quality Health Inc (QHI), sells oestrogen via its website with no age checks or consultation. It means children can secretly begin the process of changing gender at home and without telling their parents. Do-it-yourself transitioning among adults is also on the rise, largely because of long waiting lists to see specialists.

Sid Dajani, of the Royal Pharmaceutical Society, likened the practice to ‘playing Russian roulette’ with their health. He said: ‘In men, taking excess oestrogen can cause sexual dysfunction, infertility, incontinence and type 2 diabetes, which is fatal if unchecked.

Alison Specter and her husband Brett, pictured, won the company who sent out the oestrogen

‘For women taking male hormones, the risks are that they could develop extreme acne, alopecia and increased body odour. Then there are the mood swings, anxiety and possible depression. Again they have the risk of infertility and there is some evidence emerging that the use of testosterone in women is linked to cardiovascular disease and some cancers.’

Selling prescription-only medication to anyone without a prescription is illegal under the 1968 Medicines Act and carries a maximum jail term of five years.

Hormone drugs posted to customers by QHI – which is under investigation by the UK medicines regulator – usually come in an unmarked box, making it easy for children to deceive parents. One prospective customer wrote on the online forum Reddit: ‘It’s really important that I know the package will not give away its contents.’

With his parents’ permission, a boy aged 15, who is not transitioning, assisted our investigation into the trade. He obtained drugs from QHI without prescription or any questions asked.

Bertie, from Oxted, Surrey, used his debit card to buy an oestrogen brand called Elleste Solo. In a possible attempt to evade British law, the drugs were priced in euros but charged in US dollars. He bought a packet of 28 pills for €37.58 (about £33) and was later sent an indemnity form requiring him to declare he was over 18 and would take the medicine under the supervision of a doctor.

QHI does not sell testosterone, an offence that carries a maximum sentence of 14 years for those who supply it without obtaining a Home Office licence. Those who sell oestrogen unlawfully face much less severe penalties. On its website, QHI gives an address in Regent Street, Central London, but does not include a phone number. The premises turned out to be a ‘virtual office’.

The package sent to Bertie was marked Ripple Global Ltd, a company registered in Ireland but with a shabby office in Bristol. Ripple’s managing director is Alison Specter, 53. Her husband Brett, who describes himself as an entrepreneur, owns half the business.

We tracked down the Specters’ home in Spain – a seventh-floor apartment in the affluent fishing town of El Campello, near Alicante. Neighbours said they were on holiday. The property is a five-minute drive from the post office Ripple uses as a return address for drugs sent to QHI customers.

When a reporter contacted Mr Specter via Facebook, he closed his account. In Bristol, the company’s only other director, Tracy Butler, insisted Ripple was ‘an administration company. When pressed about QHI drugs, she added: ‘We run logistics for overseas… like US companies and things like that. Property and stuff.’

During our investigation, the QHI website closed down. When The Mail on Sunday tried to access the site, we were directed to a message that read: ‘We hope to restore our full website by the end of the month.’

The UK medicines regulator investigated QHI for selling prescription-only drugs online in 1996.

The MoS has spoken to parents who had no idea their children were using the drugs. One mother said her 15-year-old son bought oestrogen tablets called Progynova and spironolactone from QHI. The company also offers drugs to treat a range of illnesses, including Parkinson’s. The woman, who asked not to be named, said her son, influenced by internet chatrooms, decided he wanted to be a girl at 14. Unable to obtain an immediate appointment at a clinic, he bought hormones from QHI. He was not asked for proof of age or a prescription and simply signed and returned the disclaimer. His mother only discovered he was on the drugs five months later.

She said: ‘The fact that my son was able to purchase large quantities of drugs via this method, without the involvement of any medical practitioner, tells us all we need to know about the protections afforded to parents by companies such as QHI. Later my son did enter the gender service where, at the age of 15 years and seven months, a psychiatrist assessed him to not have the cognitive capacity to understand the consequences of his decision. The assessment was of no value, as he was already taking Progynova and spironolactone, purchased on the internet.’

The mother called for an investigation into transgender chatrooms. ‘I do not know what I could have done to prevent my son deciding to self-medicate, so I am imploring health professionals and researchers to start a discussion on potential solutions to what is a major and growing problem,’ she said. ‘I missed the boat with my son, who is now 17. She is now well on the way in her transition, all via self-medication, under the not-very-watchful eye of the medical authorities, who merely check her blood levels every four months. I truly hope she won’t regret her decision.’

Professor Gary Butler, head clinician at the Tavistock Gender Identity Service, Britain’s only NHS service for under-18s who want to change gender, said his staff dealt with young people buying hormone drugs online without prescriptions ‘all the time’.

‘For a young person hormones are very powerful and have more effect on the mind and the emotions than they do on the body,’ he added. ‘They can cause depression, euphoria and anxiety, particularly if you use too much. You don’t know what sharks are putting out under the guise of hormones.’