The founder of the Family Research Institute has urged the Supreme Court to uphold bans on same-sex marriage in order to prevent harm to gay people, claiming his research shows their lifespans are shortened by long term relationships.

Right Wing Watch reports that Dr Paul Cameron appeared before the National Press Club on Thursday to present a report on his research into homosexuality.

His report claimed to show that married gay couples have shorter life expectancies than single gay people. Based on this, he urged the US Supreme Court not to overturn bans on same-sex marriages in order “not to harm homosexuals” by encouraging their “disorder”.

He said: “The Supreme Court ought not to harm homosexuals by legitimating homosexual coupling, and the psychiatric community ought to pay attention to this enormous deficit of lifespan and reopen the issue of whether or not homosexuality is a mental disability or a disorder.”

Dr Cameron went on to make the claim, recorded in a second video, that he had looked at obituaries of gay men in San Francisco and found that 23% admitted to having sex with underage boys, which he stated was simply part of their “sexual repertoire”.

He adds that parents are wary of having their children sleep over with the children of gay couples because they “just don’t know what’s going to happen.”

Dr Cameron has previously claimed that “homosexual behaviour” reduces life span by up to 24 years, making it more dangerous than smoking.

In 2012 he said President Barack Obama’s support of equal marriage rights for gay couples lends ‘credence’ to claims that he had gay relationships, and that the “long term goal of the homosexual movement” is to force children to experience gay sex acts.