By Gary Duffy
BBC News, Sao Paulo
The couple featured in Epoca magazine
Brazilian military police have arrested an army sergeant who revealed that he was gay in an interview with a national news magazine at the weekend.
The ministry of defence says the sergeant is to be questioned about alleged desertion from the military and there is no question of discrimination.
Sgt Laci Marinho de Araujo, who suffers from ill-health, was moved from a Sao Paulo hospital to the capital Brasilia.
Human rights groups say they are concerned about his welfare.
The arrest happened just as Brazil's President Luiz Inacio Lula da Silva was due to address the country's first national gay rights' conference.
Sgt Laci Marinho de Araujo and his partner, who is also a sergeant in the Brazilian army, featured on the front page of Epoca magazine.
They gave an interview in which they talked openly about living together as a gay couple.
The two soldiers said they had been in a stable relationship for 10 years.
However, while they were taking part in a television interview on Wednesday, Sgt de Araujo was arrested by military police who surrounded the TV station until he came out.
The sergeant, who says is being treated for a variety of medical problems including multiple sclerosis, was recently absent from his unit, and the army says he is accused of desertion.
A human rights group which has been in contact with the couple says they called in desperation asking for help, and it is concerned for his welfare.
Brazil's first national gay rights conference is taking place over the next four days.
President Lula's government has hailed the event as historic.
However, despite staging what is thought to be the biggest gay pride demonstration in the world in Sao Paulo, which this year attracted an estimated three million people, gay groups in Brazil say they still face enormous problems of discrimination and violence.
Between 1963 and 2007, activists say that more than 2,800 people were killed in Latin America's largest country because of their sexual orientation.