At least four incidents of young men killing themselves after being bullied over their sexual orientation have been reported in the US in the last month.

The most recent death was of New Jersey student Tyler Clementi, who jumped from a bridge after his roommate allegedly taped him having sex with a man.

Dharun Ravi of Plainsboro, New Jersey, and Molly W Wei of Princeton have been charged with invasion of privacy after they allegedly streamed the footage on the internet.

On September 23rd, 13-year-old Asher Brown, from Houston, Texas, shot himself in the head. His grieving parents said he had been persistently harassed by other students who thought he was gay.

Fifteen-year-old Billy Lucas, of Indiana, hanged himself on September 9th. Classmates said he had been bullied for years over his sexual orientation.

Another 13-year-old, Seth Walsh from Minnesota, died in hospital on Wednesday, eight days after attempting to hang himself from a tree. He is said to have endured taunts and abuse for being gay from other students.

It is unclear whether suicides for young gay men are up, or if there has been better reporting of their deaths. LGBT students are known to be at a higher suicide risk than their heterosexual peers.

No one is expected to be charged over the harassment which led to the deaths of the three younger boys.

In Seth’s case, police found that no crime had been committed.

In Billy’s case, a Facebook memorial set up for him was hit by more homophobic abuse, as well as apologies from some of the students who had harassed him.

Meanwhile, Asher’s parents say they repeatedly complained to his school about the persecution but officials did not take the reports seriously.

One report claimed that Asher had come out to his stepfather on the morning of his death. The Houston Chronicle reported that the boy’s stepfather accepted his declaration.

In another tragedy, 19-year-old Rhode Island student Raymond Chase hung himself on Wednesday. The student was openly gay but it is not clear whether he had been bullied.

The deaths have shocked America and lesbian chatshow host Ellen DeGeneres implored the country to take action and prevent further deaths.

Speaking on her daytime show yesterday, the presenter said: “Something must be done.

“This needs to be a wake up call to everyone that teenage bullying and teasing is an epidemic in this country, and the death rate is climbing.

“We have an obligation to change this.”

On Clementi, whose body is thought to have been recovered from the Hudson River, she added: “He was outed as being gay on the Internet and he killed himself… One life lost in this senseless way is tragic.”

New York-based gay rights group Empire State Pride Agenda said in a statement. “It is difficult to say if this is a trend, or if our society is becoming sensitive to this kind of story that we have heard far too often in the LGBT community.”

Judy Shepard, mother of the late Matthew Shepard who was killed a decade ago for being gay, called for schools to be made safer.

“Our young people deserve better than to go to schools where they are treated this way,” she said. “We have to make schools a safe place for our youth to prepare for their futures, not be confronted with threats, intimidation or routine disrespect.”

Forty-four US states have anti-bullying laws, but gay campaigners complain that many are not comprehensive enough and do not detail what bullying can involve.

Since Billy Lucas’ death, Indiana legislators have promised to tighten laws to help prevent future tragedies.

The rapper 50 Cent has come under criticism for suggesting that men who do not sleep with women should kill themselves. “If you [are] a man and your [sic] over 25 and you don’t eat pu**y just kill yourself damn it. The world will be a better place.” The star, real name Curtis Jackson, posted the message shortly after the death of 19-year-old Tyler Clementi.