For these women sex can be anything from painful to potentially fatal.

Three in 25 women are actually allergic to sex.

It is tempting to joke about the idea of an allergy to sex isn’t?

Not tonight dear I have an allergy.

But there is nothing to laugh at for the three in 25 women who experience this painful condition. A semen allergy is a rare but very real condition that affects up to 12 per cent of women. With one expert claiming that some women can experience anaphylactic shock just one hour after exposure.

And there is even the potential for a fatal reaction.

Sperm allergy or seminal plasma hypersensitivity is an allergic reaction to proteins found in a man’s semen. The symptoms can stem from redness, swelling, pain, itching, and burning sensations in the vaginal area to more extreme symptoms such as flu-like illness, extreme fatigue and difficulty concentrating.

For women suffering the rare, but frustrating allergy it can hard to come to terms with.

One woman who has spoken out about the condition, under a pseudonym, says it began for her when she was in her 30s.

Now in her 50s she says she saw GP after GP trying to track down the cause of her discomfort.

“All the doctors dismissed out of hand my suggestion that I was suffering a physical reaction to sex,” she told The Daily Mail.

“They said such things did not happen and implied my partner could have been unfaithful - which was insulting to both of us.”

Finally the woman, now the mother of a teenager,  was referred to a genitourinary clinic and diagnosed with the allergy.

“We didn't want to be using condoms, but the solution did work," she said.

According to Dr Sam Hay, the host of Embarrassing Bodies and contributor to The Glow it does happen “I swear I’ve seen a patient with this; she gets significant allergy-like symptoms when her partner ejaculates inside her,” Dr Hay said. “I have read about it and it does happen.”

One woman writing for website XO Jane said that she developed Human Seminal Plasma Hypersensitivity fourteen months after she married her partner and it led to an eventual breakdown of her marriage.

“Every time we had sex, there was immediate pain and a burning sensation. The area would become red and swell up, then over the next week the skin cells would shed and fall off. I would be left in agony and the pain lingered for days...

Finally I got a referral to another gynecologist and when I described my symptoms, he suggested I was allergic to my husband’s semen.

"You’re definitely allergic to him,” he said. “But there isn’t anything we can do to help. There isn’t a cure. You’ll just have to learn to live with it.” My world came crashing down. The next few weeks were filled with tears and I truly felt shattered. The doctor suggested we use condoms, but one of the side effects of the symptoms is I had an allergy to latex, too.

Over the next four months, many deep and meaningful talks occurred with my husband. He desperately wanted to become a father and I didn’t want to deny him his dreams. This wasn’t something we could live with.

We eventually made the heartbreaking decision to separate."

Doctors say about three per cent of women with fertility problems have a sperm allergy so it is worth checking out. Women need to keep in mind that this allergy doesn't have to end relationships. It can be managed, or even cured.

For an experts answer to semen allergy watch this video. Post continues after video.

The cure for the condition in many cases is condom use, but if you are trying to fall pregnant an alternative method is desensitisation therapy including administering allergy shots containing small doses of the male partner’s semen, and the couple to engage in sex two or three times a week.

What is surprising about the allergy is that it may take place the very first time a couple have sex, or may happen suddenly with a long time partner.

The condition is so rare that women find they can go to many professionals before the allergy is discovered.

It is often is misdiagnosed as vaginitis (inflammation of the vagina), a yeast infection, or a sexually transmitted disease (STD) like herpes.

According to the International Society for Sexual Medicine one clue for diagnosis is condom use.

“If sperm allergy is present, the woman should not have any symptoms when she and her partner use a condom. The allergic reaction should only happen during unprotected sex.”

Dr Michael Carroll, a lecturer at Manchester Metropolitan University has said that in fact it might be more common than we think as woman are too embarrassed to seek advice with a GP.

Women suffering the condition urge others not to go through what they did  and to make sure they seek out help because it is available.

Have you experienced a semen allergy? What advice do you have for other women? 

Want more? Try this.

 This is what people google about sex.

I've been in this relationship before and it is not healthy.

For more on painful sex and possible causes go to The Glow.