They pleaded guilty to the charges and were placed on probation.
They were 15 years old at the time of the offence and it is contended that they believed their secret was safe until one of the parents found out and reported the matter to the police.
A policeman commenting on the issue said the parent who made the report must have been frightened when the girls were charged.
"Sometimes, it is the girls who are the aggressors but, in times past, it is the poor boys alone who had to face the consequences in court," the policeman said.
"I am glad the law has been changed, so girls can be charged along with boys. Children are sent to school to learn, not to be involved in sexual acts.
"This case should be a warning to schoolgirls. Once they are caught, and in agreement with boys, they, too, will be arrested and charged. They may not have to face jail time but the embarrassment of coming to court should be a deterrent for them.
"I have observed many schoolgirls, while on duty, and some of them are really out of order. Sometimes they are teasing boys and forcing them to be intimate with them. Last month, I had to give some schoolgirls a stern warning when I heard the type of argument they were engaged in.
"I think the principals, teachers and guidance counsellors at schools should have weekly counselling sessions with girls and inform them that, under the law, they, too, will be charged for being involved in sexual activities with boys. However, boys, too, must take heed and avoid 16 contact with girls even if girls try to pressure them," he said.
Section 10 of the Sexual Offences Act states, "A person who has sexual intercourse with another person who is under the age of sixteen years commits an offence"
This is the section under which the four children were charged.