Some have sex for wrong reasons
Most of the girls involved in underage sex cases are victims, manipulated by older men into having a sexual liaison.
But there are also those who seek out sex for company or money.
Some openly call out to "sugar daddys" to finance their lifestyle. Others are lonely and want company, only to find the wrong type online.
But the law is clear; the girls' lack of maturity means they must be protected.
Mr Shashi Nathan, a partner at KhattarWong LLP law firm says: "The men know the law, so there shouldn't be an excuse for them to do all of this.
"If they know that the girls are young and still want to be involved sexually with them, they should be punished."
What then of girls who have sex for cash, even when they are underage?
In 2008, the law was amended making commercial sex with a minor below the age of 18 an offence that carries a jail term of up to seven years, a fine or both.
The argument then was that young people, because they were immature and vulnerable, should be protected from providing sexual services.
But lawyer Gloria James-Civetta of Gloria James-Civetta and Company said there is a need to implement something in the law to keep the girls on the right path.
She added: "The law has been changed by The Women's Charter, so there is no law to charge these girls. The men are given the brunt of the punishment."
Who are these girls?
"These girls usually do not have a close relationship with their families and this results in little guidance as the parents are not involved in the kid's life," said Ms Frances Yeo, a psychologist at Thompson Pediatric Centre.
She said some girls also may have deep emotional attention problems and these relationships may help them feel good about themselves.
"It all goes back to how secure they feel about themselves. With no love at home, they will have a void in them and they try to fill it," she said.
And of those girls who trade their modesty for branded handbags, Dr Carol Belhetchet, senior director for youth services and clinical psychologist for the Singapore Children's Society, said: "We live in a indulgent society and everything is getting more expensive.
"With the competition with friends to do better, these wannabe adults do such things to attain their goals".
- Darishini Thiyagarajan and Melody Ng