Health Minister Edwin Poots displayed prejudice in maintaining a lifetime ban on homosexual men giving blood in Northern Ireland, the High Court heard today.
A judge heard claims that the Democratic Unionist representative's stance went beyond religious beliefs.
Lawyers for an unidentified gay man challenging the prohibition also revealed their client is a Christian who is equally opposed to homosexual activity.
They are seeking a ruling which would bring Northern Ireland's policy into line with the rest of the UK.
The complete prohibition, put in place during the 1980s AIDS threat, was lifted in England, Scotland and Wales in November 2011.
It was replaced by new rules which permit donations from men whose last sexual contact with another man was more than a year ago.
The 12-month deferral was left in place following a Government Advisory Committee report.
It identified a much shorter a window period during which infection with blood-borne viruses could not be detected.
Mr Poots has so far maintained the ban in Northern Ireland, declaring it was to ensure public safety.
Attorney General John Larkin QC, who is representing the Department and the Minister in the case, is expected to argue that no definitive decision has been taken.
Mr Justice Treacy was told the lifetime prohibition was disproportionate, with an estimated one additional HIV infection per billion blood donations if a 12-month deferral period was introduced.
According to counsel for the applicant the Northern Ireland Blood Transfusion Service receives 64,000 annual donations.
David Scoffield QC said: "Working that figure into the increased risk of one infected donation per billion, we estimate the Minister is concerned about an additional infected donation being made roughly every 50,000 years."
He also argued the risk could actually reduce with greater compliance to the proposed new rules.
In a wide-ranging challenge claims of irrationality and discrimination were advanced.
Turing to allegations of apparent bias, Mr Scoffield contended that the decision went against the advice of Mr Poots' officials, the chief medical officer and an expert advisory body appointed to guide UK health ministers.
"Without consultation with the Assembly Health Committee or with other interested parties this decision has the hallmarks of a reactionary response," the barrister said.
Rejecting any contention that no final decision has been taken, he claimed: "What the Minister is waiting for is these proceedings to be concluded and for everyone essentially to forget about this issue so he can simply maintain the status quo."
He told the court his client is a Christian man whose theological views on homosexual acts are similar to those of Mr Poots.
"Although the applicant, perhaps curiously in these circumstances, shares the view that homosexual practice is wrong, he simply takes the view that homosexuals should not be banned from giving blood," Mr Scoffield said.
"The applicant's case is that the approach displayed by the Minister on this issue goes beyond the expression of orthodox religious views and amounts to prejudice."
It was argued that the issue should have been put before the Stormont Executive, given the level of opposing views among other MLAs.
The court heard how former Ulster Unionist deputy leader John McCallister claimed Mr Poots was misleading in his reasons for maintaining the lifetime ban.
Michelle Gildernew, Sinn Fein chair of the Stormont Health committee at the time, was equally vocal in her opposition.
Mr Scoffield argued the rival politicians had a legitimate interest and had formed the view that prejudice was involved.
He insisted: "There's more than enough evidence for this court to conclude that the fair-minded observer would conclude there was a real possibility the decision was infected by bias."
The case continues.