"That's what the expectation in our society is," she says.

But the reality is more complex.

Dr Parekh is a Canberra medical doctor and forensic expert often called by prosecutors to give evidence in criminal trials. She also does defence work.

In some trials, prosecutors call Dr Parekh to give expert evidence on the different types of responses to sexual assault.

"I think that's really important," she says.

"Because the common perception by the general public, but also by jurists who comprise the general public, is that people will fight back.

"And if you think about how terrifying a domestic violence or sexual assault situation is, the commonest response is to freeze."

Dr Parekh was working as a physician when, back in 2000, she became involved in the case of a 15-year-old girl who had been raped.

There was no forensic medical service in the ACT at the time, and the government approached Dr Parekh to head one up.

The team and services have expanded in the years since.

Dr Parekh now holds the role of director of Clinical Forensic Medical Services, which includes Forensic and Medical Sexual Assault Care and Clinical Forensics ACT.

Dr Parekh says there is more than one type of response to sexual assault.

Fight or flight might be the expectation, but most of her patients describe a feeling of being paralysed or unable to move, she says.

Imagine it was 3 o'clock in the morning.

"You're lying in your bed and you hear a loud noise. You actually can't move, can you?" Dr Parekh says.

"It's actually well-preserved, right through the animal species. So if you imagine a big eagle going over a field of mice, it's the ones that run that it will spot."

Another type of response is called surrender, or negotiate.

In this type of response, a victim might say if the attacker stops hurting them they will have sex with them, or negotiate with them to use a condom, or be quiet so the kids won't hear.

Dr Parekh said it's also possible that a person would display more than one type of response.

None of the responses imply consent, she says, but often responses other than fighting cause the victims to question their response.

"It's really common for patients to say to me, I must have wanted this to happen because I didn't fight back," she says.

The response can also have a varying impact on physical injury.

A victim of sexual assault and who has either frozen, surrendered or negotiated, will likely display fewer - or no - physical injuries than a person who has fought back.

And that can have an impact on a person's healing, she said.

The doctor recounts a case that illustrates the effect a visible injury can have on a person. In the case, a woman had been stabbed and raped and left for dead.

When the woman saw Dr Parekh at court months later, she told the doctor how well she was doing and how her life had changed.

Dr Parekh said the woman had a big scar down her neck. "So she could say, 'I was raped and I've got something to show for that'."

What Dr Parekh and her team cannot tell investigators, or a person, who might have been unconscious when they suspect something happened, is if a person has had sex.

Dr Parekh says that of more than 2000 patients the clinic was involved with, there were about three female perpetrators and the rest were male.