Was it unfair to jail the Dublin Female Teacher who had sex with her 16 year old pupil?

Nope. If ya can't do the time, don't do the crime. 

Where were all these hot teachers when I was at school?

No, it isn't unfair. That's illegal.

No. Regardless of the age of the teacher or the age of the pupil, getting sexual with your own pupil is very unprofessional...and often an abuse of authority.

She should have at the very least had the pupil transferred to another teacher

The age of consent to sexual activity is 17 in ROI so it is a criminal offence to have sex with a person under 17 years of age, additionally it is a criminal offence for someone who in authority such as a teacher to have sex with their student regardless of their age......... so x2 criminal offences and when she comes out of prison she has no career and she will find it almost impossible to get a job anywhere as a registered sex offender

Er, no - the same rules apply whether it's a male or female teacher. 

I am sure the poor boy suffered. ...when he lost his happiness with his teacher.

Lose job, yes... jail, no. You can't rape the willing, and l doubt he could perform under duress. He wanted it.

yes as the teacher is an adult the student a minor = sexual assault of a minor