Defence lawyers for 26 Egyptians accused of "debauchery" at a Cairo bathhouse challenged police procedures in the case on Sunday.
The men were arrested on December 7 in a night raid on a hammam in the Azbakeya district of the capital.
Egyptian law does not expressly ban homosexuality, but gay men have previously been arrested and charged with debauchery instead.
Defence lawyer Tareq al-Awdi on Sunday accused the policeman who led the raid of falsifying his report.
“Thirty-three men were arrested and the officer later freed seven of them. That wasn’t in his report, which is illegal,” Awdi said.
Nor did he mention that he had authorised the arrests to be filmed.
Islam Khalifa, defence lawyer for 14 of the defendants, said the officer claimed that all the suspects were homosexuals, but medical reports proved this was not so.
Controversial medical tests — condemned by international human rights groups — have long been used in Egypt to identify suspected homosexuals.
Third defence lawyer Khaled al-Nakkash said his client had been told by police to remove his clothing before being taken out of the bathhouse.
A private television channel subsequently broadcast footage of men in underwear or with towels round their waists after the raid.
An AFP journalist in court said the case was adjourned until Monday after a hearing lasting for two hours.
In the past, homosexuals in Egypt have been jailed on charges ranging from “scorning religion” to “sexual practices contrary to Islam”.
On December 27, an appeals court reduced jail sentences given to eight men over a gay wedding video that went viral on the Internet to one year each, from three years.
They had been convicted in November by a lower court of broadcasting images that “violated public decency”.