Student-Teacher sexual relationship: should there be exceptions?

A 25 year old Spanish teacher was arrested for having sex with her 18 year old student on May 25 in Texas. Now, her arrest is "raising questions about the law" of convicting a teacher who indulges in a sexual relationship with his/her student. In this case, both the 'participants' were/are consenting adults. Should the teacher be convicted? (20 years of imprisonment is the verdict if she is found guilty)

You can read more about this incident here:
http://articles.news.aol.com/news/article.adp?id=20060611131209990005

The law upholders are arguing that the teacher took advantage of a young child. I do agree with them to a certain extent but I also wonder if the two were not in a student-teacher relationship, would their sexual relationship be objected to? I asked a friend, who is now thirty, if he would have dated an 18 year old when he was 25. He said he would have. There were plenty of 25 year olds hitting on me when I was 18. There are plenty of 25 year olds who hit on and/or are dating 18 year olds now. No one seems to have an objection against that since both the parties involved are above the legal age of 18 and are consenting adults. On the other hand, in the case in question, the relationship is objectionable because it involves a teacher and her student. If the two had met 'outside' of school setting, there would have been no problems but now that, unfortunately, they met 'in' a school setting, the accused faces nearly 20 years behind bars if convicted.

I certainly don't commend teachers sleeping with their students but neither do I think that 20 years of imprisonment is acceptable in this particular case. If the student was not an adult, I would not have argued against the arrest or the prospective sentence but TWENTY years just sounds so harsh for this particular scenario. I am sure that even Beccario would disagree with the Texan Law at this point of time. Beccario states that punishment had a preventive, not a retributive, function; punishment should be proportionate to the crime committed; the certainty of punishment, not its severity, would achieve the preventive effect. Considering that, I, personally, believe that the teacher MUST be fired from her job, not allowed to teach again, and be put on probation for a certain period of time if need be ... but 20 years of imprisonment? Sounds ridiculous.

This is more of an ethical issue than it is legal. Should a teacher never develop feelings for his/her student and vice versa? Same applies to other professions as well though. There was a case in rural Canada somewhere a few years ago where a doctor was expelled from the local physicians association for he married one of his ex-patients. It violated the association's terms in regards to medical ethics wherein a physician can't have a sexual relationship with his/her patient. The reason why such relationships are disregarded are to protect patients from being exploited when in a vulnerable state. Similarly, a student-teacher sexual relationship is criminalized to avoid students from being exploited by their teachers. Therefore, I have absolutely no qualms about throwing teachers into jail who prey upon their students ... but should a teacher who slept with an adult student be punished equally as harsh as a teacher who invited a 14 year old boy into her cabin and raped him?

Curious.