As more and more women are remaining single - and childless - Mahidol University's Institute for Population and Social Research has decided to look deep into why, as well as into where all the men have gone.
The institute's discoveries have proved crucial for the country to prepare for emerging population trends.
Thailand is turning into a greying society, as its birth rate plunged to just 1.6 per woman in 2013 from six in 1970.
Men have indeed gone missing because of their higher mortality rate.
This has led to a gender imbalance in the marriage market. To be exact, there were 782,716 more females than males between the ages of 15 and 49 in 2010.
Sutthida Chuanwan, who works for the institute, said sexual preferences, lifestyle patterns and women's higher confidence in their social roles and status were also key factors.
Thai society is more accepting of varied sexual preferences, she said.
"There has been a change where men are partnering with men and women are partnering with women. This results in an unequal distribution between men and women."
Men who like men accounted for 3 to 17 per cent of the population in 2010.
In the frame is also procrastination in matrimony by both sexes.
The average age for men to get hitched has soared from 24.7 in 1970 to 28.7 in 2010 and for women from 22 to 24.9.
The study by Sutthida and Piyawat Katewongsa also reveals that women's growing confidence in their self-reliance and their independence, higher education and career advancement opportunities have influenced their decisions to stay single.
The lower marriage rate has led to lower birth rates, which could pose problems for future years, so efficient policies |must be planned and imple-mented.
Suporn Jaratsitm, a researcher at the institute, said Thailand could learn from Japan's example.
"Japan's demographics are similar to Thailand's, but it has faced these issues far longer than we have," she said.
New policies there require people to work until 65 instead of retiring at 55 and encourage them to adopt the "Angel Plan", or have more children.
Japan also offers welfare benefits such as paid pregnancy leave and day-care centres so that more working women agree to start or build a family.