Criminal Law
Rape by Fraud
Rape can be committed by fraud in the factum, however this is very rare. The more common type of fraud, fraud in the inducement is generally not rape.
An example of fraud in the factum rape is when a victim consents to examination by a doctor, but the doctor engaged in sexual intercourse with the victim instead.
Basically any time someone agrees to have sex with another, they have consented to sex so it cannot be rape. Some jurisdictions have criminalized specific situations however, such as impersonating someone's spouse, such as at night in a dark bedroom.