The man said that was a "possibility''.
But he said he designed the website for travel purposes and could not see how anyone could take it any other way. He has denied the charges.
Ms Walker also asked about the man's business partner who was based in Thailand and had been facing charges relating to underage sex.
The man said his friend had been acquitted of all the charges.
The 47-year-old said the website was designed for a range of customers but said his first and only customer was a man who identified himself as Michael Gray.
Recorded conversations between the man and Mr Gray have been played to the court and include discussions about sex with under-age boys in Thailand.
Mr Gray turned out to be an undercover police officer.
The accused man said he organised a diving trip for Mr Gray and a visit to a national park but felt uncomfortable when the subject of underage sex came up.
"For me, my first reaction was: `Oh no, I'd really rather he didn't'.''
He said he was "wary of the whole idea''.
The man told the court that he first went to Thailand with his father, who was a missionary, and visited refugee camps.
"On subsequent visits I went back because I had realised there was a large gay scene in Thailand.''
He said his sexuality was defined as "ephebephilia'' which was a preference for boys who had gone through puberty.
And while he had used the term "boy'' as a search engine for his Thailand tourism company, it referred to young men who worked at go-go bars, all of whom had to be over the age of 18.
In his opening statement, the man's lawyer Chris Wilkinson-Smith said the gay community and the police had at one point been on opposite sides of the law and there was "real territory for misunderstanding''.
He said his client told Mr Gray that he did not want to do anything illegal, and did not make any bookings in hotels which allowed sex with underage boys.
