Actor Vivek Oberoi believes that crimes against women can only stop when women start to sensitise the men in their family towards the opposite sex.“Every mother should teach her son to respect every girl. That is where it (the change) will start. If he says something (wrong) about a girl, then she should slap him. Then we will learn,” the 36-year-old said on the sidelines of an event on Thursday.“I think women can protect women in the future, the greatest service by instilling in their children, brothers and husbands, the right values for women. Respect for women is not an option, it is a necessity,” he added. He was speaking in connection with the brutal gangrape of a Delhi girl who is now fighting for life in a Singapore hospital.