Nearly one in three secondary school students is not against the idea of premarital sex - although very few say they indulge.
Findings of a survey also suggest 10percent and 13percent of youngsters are accepting of multiple sexual partners and extramarital affairs, respectively.
The survey of 3,376 students from 11 secondary schools was conducted from January to March by the Society for Truth and Light. Respondents were asked to rate values and their parental relationships on a scale of one to six, with one being the least important.
"Those who are at higher risk of premarital sex include students with poor relationships with their parents and who place less importance on ethics and marriage," society chairman Lawrence Lour Tsang-tsay said.
Those who engaged in premarital sex rated the importance of "ethics and marriage" and "relationship with their parents" an average of 0.4 lower than those who did not engage in intercourse.
Another factor indicating acceptance towards premarital sex is the value a student places on personal freedom and satisfaction, the survey found.
Lour said there is a connection between watching pornography and engaging in premarital sex. "Of those who engage in sexual behavior, 50percent had watched pornography before."
Only 105 of the 3,376 respondents - 3.1percent - said they have engaged in premarital sex. "The statistics have been consistently low across the years, and are very low compared to Western countries, which have an average statistics of 45percent," Lour said.
Similarly, the results of a separate global study revealed that Hong Kong youngsters are much more conservative when it comes to sex compared to counterparts in South Africa, Singapore, Mexico, Sweden, India, Britain, Russia, Germany and the United States.