When Pope Francis goes to the White House next week as part of his US visit, among those who have been invited to greet him are two openly gay Christians, a radical nun and a transgender.

According to Fox News, gay former Episcopal Bishop Gene Robinson, gay Catholic blogger Aaron Ledesma, Sister Simone Campbell and transgender Vivian Taylor have been invited by the White House to meet the pope, but it's not clear if they will have a face-to-face meeting with the head of the Roman Catholic Church.

With the White House invitations sent to these controversial personalities, the Catholic watchdog Lepanto Institute is accusing President Barack Obama of forcing the Pope to give his nod to homosexuality and socialism during his visit.

"This is definitely out of the ordinary," said Michael Hichborn, Lepanto president. "[President Obama is] trying to force the pope into a situation where it seems as if the Church is giving licence to homosexuality and socialism."

Hichborn opposes the ideas of those people whose lifestyles are in contradiction to the Church's teachings espoused by the Pope.

"You don't treat the head of the Roman Catholic Church as a political toy in order to push your own agenda," Hichborn said.

White House spokesman Josh Earnest said the list of guests has not actually been released. "I'd warn you against drawing a lot of conclusions of one, two or three people on the guest list because there will be 15,000 other people there," Earnest said.

It is unlikely, Hichborn said, that Pope Francis will address homosexuality in his US trip as "he doesn't tend to take things on directly."

In 2013, Pope Francis declared "If someone is gay and is searching for the Lord and has good will, then who am I to judge him?" This statement led some gay rights advocates to conclude that the Catholic Church's view on homosexuality is shifting towards acceptance.

Meanwhile, advocates for gay and transgender Catholics have asked to meet the pope during his visit in Philadelphia on Sept. 26 and 27, the Boston Globe reported.

The Vatican has not responded, according to DignityUSA, an advocacy group for LGBT Catholics.

Gay Catholic Ron Belgau is a featured speaker at the Vatican-approved World Meeting of Families in the US.

Ledesma said he has been inspired by Pope Francis. "When you have someone in that kind of position saying compassionate, loving statements like that, that's what's going to draw the Catholic community together. That's what's going to draw the estranged Catholics back in," Ledesma said.

Bishop Robinson said, "If Pope Francis is to be believed in all the kindly pronouncements of his first year (and I do), his good tone should be followed by the tough work of changing the systems of belief, doctrine and religious practice which perpetuate the victimisation of those he seeks to serve," according to the Daily Beast.

Sister Campbell is supporting Obamacare, including its contraceptive provisions, which is opposed by the US Conference of Catholic Bishops.

Taylor said she was allowed to bring five guests and chose three transgender people and two others, according to CNS News.

"I'm very happy to meet my brother in Christ, Pope Francis," Taylor said. "I'm glad we can bring some LGBT representation to the event."