Female wanting to join the FBI / NC SBI?

If you were a police officer then I would say it would be harder for women because they need to have a higher self awareness and officer safety because they are usually smaller and they are always out taking calls interacting with the public. The FBI is a investigative agency, they don't go out and answer calls for a full 8 hour shift constantly interacting with the public. However, if you are a field agent then it could be harder because you would be out interacting with people, but still not as much as a police officer.

But in forensics there is no advantage/disadvantage to being a male or female.

Also, the FBI would give you more options but it would be a harder agency to get hired on with. You have to have a very, very clean record plus a Bachelors degree plus 3 years of professional work experience. However, you would get paid more, and you would get better benefits, but like you said you would have to accept country wide placement, they may even want you to go to a foreign country depending on what specific job you have.