Adultery is not a criminal offence, neither is sleeping with a student so long as it is consensual and she is not a minor. The latter may constitute a breach of the Uni's Code of Conduct, but that is a matter between the Uni' and the Professor - contract between employer and employee. Being horny is not in itself a crime, on the contrary it may well be a sign of a well rounded personality i.e. not the scholar type that only knows how to memorise and regurgitate. But of course, while not being a crime one has to remember "there is a time and place for everything, a time to sow and a time to reap, a time for war and a time for peace, a time to live and a time to DIE ..." The crux of the offence is sex FOR grades equals corruption and it is for the prosecution to prove all the required elements of the crime beyond reasonable doubt which is a high threshold. The accused does not have to prove anything, he just has to cast reasonable doubt. If after presenting all its evidence, the prosecution has not made out a prima facie case, the defence may not even be called and the accused is acquitted there and then but this is very rare in Singapore especially at the Sub-courts level which is the level for the Prof's case because Sub-court judges are unduly deferential to prosecutors. Don't know why, maybe no backbone unlike Shadrake.