An elderly Belgian man has discovered that his 48-year old wife is a surgically-altered male.

After 19 years of marriage, “I feel I’ve been assaulted,” he told a Belgian newspaper, Het Nieuwsblad.

“I thought she was an attractive woman, all woman… [and] even during sex, I never noticed anything,” said the 64 year-old man.

The deception unraveled after the transsexual began frequenting nightclubs and getting emails from other men.

“I pushed her against the wall and said. … ‘Are you a man?’ She then announced that she was born as a boy and that she had been operated on. She was now a woman, and so she did not need to tell me about her past as a man,” the husband said.

“My world collapsed. That evening came to blows. The police came.”

He’s now trying to annul his marriage to his 48-year old male “wife,” but a local court has yet to decide the case. They’re still living together.

The pseudo-wife underwent a sex change before he entered Belgium illegally, and worked as a nanny for the man and his first wife.

The man fell for the nanny, divorced his wife and got a marriage license for the male-nanny, and then fought Belgium’s immigration authorities to win residency for his new “wife.”

Immigration authorities initially refused, because they though the immigrant’s documents were fake.

“The Belgian courts had serious doubts about the authenticity of her birth and her identity papers, but eventually they accepted it anyway,” he told the newspaper.

Documents are a hot-button issue for transgender activists, who represent men and women who wish to live as the other sex.

Groups such as as the D.C.-based National Center for Transgender Equality want people to be able to change the sex marked on their birth certificates, drivers’ licenses and passports — even if they have not undergone the difficult, expensive and mostly irreversible sex-change surgery.

The legal ability to change all identification documents — including birth certificates — likely would cause additional cases of sex-related deception.

That’s because sex-change surgery can be very credible, especially if it is undergone by young males before puberty.

Aided by hormone injections, transsexual males can gain female-like sexual organs, minimize their facial hair, and even gain weight around the buttocks rather than the belly, as men can.

Women who undergo the process can gain male-like organs, as well as weight around the belly and male-pattern baldness once they age.

Many feminist groups and gay-advocacy groups, such as the D.C.-based Human Rights Campaign, support the creation of novel rights for people who wish to live as the other sex. They want people to be allowed edit their birth certificates and have to easy access to so-called “gender-neutral” bathrooms or university dorms.

Those would-be rights are shared by some gay and feminist groups because they tend to minimize the recognition of gender differences in culture and law. For example, many employers require their employees to buy and wear clothes that match customers’ expectations for attractiveness.

The activists’ gender-erasing goal complements their other demands that society applaud single-sex relationships, and remove legal or cultural practices that curb professional women’s workplace advances.

Social conservatives say they oppose this sex-erasing agenda because it greatly hinders the ability of parents, schools and civil-society groups to tailor kids’ and adults’ activities — in education, play and sports — to complement the normal, genetically-ingrained preferences of normal males and females.

However, laws and cultural practices that complement the vast majority of Americans leave the extremely small percentage of transgender people in the population — roughly 0.2 percent — facing a lifetime of scorn, legal hurdles and workplace obstacles, say transgender activists.

Gays and lesbians are far more numerous that transgender people, and comprise roughly four percent of the population.

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