This is a classic scenario where people are dating. Maybe it's their first or second date, and both parties are drinking alcohol and getting drunk. Then, some sort of sex act occurs, and later on, one of the parties believes that they were taken advantage of because they were drunk. Rape charges are defined under California Penal Code 261.
So, then the police come and arrest the defendant, and they charge him with, basically, rape of an unconscious person. This has to do with someone who either took drugs or alcohol, and then somebody takes advantage of that person and has sex with them. See CALCRIM 1047 jury instructions on sexual penetration of an intoxicated person.
However, sometimes the person who has been arrested argues that we were both drunk, and I thought she had consented. As I recall, she was okay with it. I didn't force her to do anything.
So, that is a potential defense in a sex crime case. Not so much because someone can say, well, I was drunk, so I shouldn't have been charged with a crime, because voluntary intoxication is not a defense in California for many crimes.
In some cases, it can mitigate the consequences. In specific intent crimes, voluntary intoxication can be used as a defense; however, in general, especially for general intent crimes, it cannot be used as a defense in California. Learn the difference between rape and consent in California.
Potential Valid Defense Strategy
That being said, if the scenario is such that two parties have sex, both are intoxicated with alcohol, and one party is claiming that the other person took advantage of them.

However, they can't remember much of what happened, and the person who allegedly took advantage of them can't remember much of what happened; that's a situation — in my opinion — that's ripe for a defense. You need to avoid making mistakes if accused of a sex-related crime.
In other words, it's just like a rape case where everybody's sober. If two people have sex and they both agree to it, then there's no crime there. Just because somebody has regressed afterward doesn't suddenly turn it into a crime. Therefore, you will need to consider the surrounding facts and circumstances.
Usually, in sex crimes cases — especially in a rape case — someone's going to get a SART exam done, which is a sexual assault exam, to see whether or not there's any DNA.
To see whether or not they have injuries that are consistent with being raped. Tears to the vagina and other such evidence, and then the SART nurse and doctor would usually give an opinion as to whether or not they felt that person had been forcibly raped.
In scenarios where two people are drunk and they have sex, again, just because somebody has regressed later doesn't mean that it was rape. Typically, I see the police prosecuting the case or handing it over to prosecutors when one party is drunk and the other is sober. Then the sober party takes advantage of the drunk party and rapes that person.
Obviously, rape of an unconscious person is a very serious crime in Los Angeles and throughout California. Therefore, if you're charged with this crime, you should consult an attorney immediately. Answer no questions from law enforcement and let the attorney guide you through the process.
Retain a Lawyer To Guide You Through the Court Process
But when you really get down to evaluating whether two drunk people can be involved in some sort of sex crime. What it's going to boil down to is logic, common sense, and the surrounding circumstances of whatever happened.
If the average person, after hearing the story, would say, well, wait a minute, you can't get somebody for rape under those circumstances. That sounds like you have a good defense there.
If, on the other hand, an average person would say, well, wait a minute, this looks like somebody took advantage of another person here; now you've got a problem. So, a lot of this information requires careful evaluation. You have to look at all the evidence in a case.
Sometimes, when the police do the investigation in these sex crime cases, they don't look at everything. They only look at one side of the story. They don't consider the other party's perspective.
Obviously, that's where your sex crime defense attorney comes in to show the facts and circumstances most favorable to you. To see if the prosecutor will dismiss the case, not file the case in the first place, or prove to a jury that you're innocent.