A 25-year-old Dublin man who had sex with a 13-year-old girl he met on a social network site after he claimed to be 19-years-old has been jailed for two years.

Graham Doyle of Ronan's Way in Clondalkin was 23-years-old when he used a false name and photograph and said he was 19 on the Bebo website.

He befriended the teenager on the site and on Facebook and exchanged phone numbers.

They later met and had sex twice at his family home.

He told his father he was giving the girl guitar lessons.

Judge Mary Ellen Ring said Doyle had built up contact and trust for months with the young girl through the internet, which made it easy for him to bring her to his house.

The delicate issue of sex had already been mentioned through text messages. The use of the internet and social media to do this was an aggravating factor.

She said it was clear from his ability to lie to his father about why the girl was in his house that he was conscious of his wrongdoing.

His gift of alcohol to the girl afterwards "smacked of a pay off".

She sentenced him to three-and-a-half years and suspended the final 18 months.

The sentence was back dated to July last when he pleaded guilty. However, he did not go into custody until October. He must also undergo 18 months of post release supervision.

The offence was uncovered after the girl's mother overheard her complaining to a friend about what had happened.

She later went to her local garda station where she was in a distressed state and made a complaint.

The girl said she was frightened at the time because he was older and bigger than her. He had assured her they would not have sex if she gave him oral sex.

However, he went on to have sex, including anal sex.

He was arrested in May 2011 after the girl identified the house she had been taken to.

He admitted the offence and said he knew the girl was 13 and claimed she had consented to all sexual activity. He pleaded guilty to two charges of defilement of a child.

Judge Ring had previously adjourned the case after hearing the evidence as she was concerned he had "groomed and targeted" his victim.

She said she was troubled that he specifically used a website used by young people.

She was later told by a clinical psychologist that the man did not have paedophilic tendencies but gravitated towards younger people because he was more comfortable with them.

His defence counsel said he was genuinely remorseful and had attended counselling.

The judge said she took into account his early guilty plea, the fact that he had shown remorse and paid his victim €5,000 as an expression of that remorse.

She had also received testimonials about his work and educational record.

However, she said sex offences had a well-known effect on victims and that they could alter the course of their lives or destroy their lives.

If he had gone to trial and been convicted it may have merited a sentence of six or seven years.

He had pleaded guilty early and had co-operated fully and his remorse was genuine, she said.