Pregnancy. In the "old days," any female who got pregnant could request a discharge and get it automatically. Those days are gone. Pregnant female members may REQUEST a discharge, but such discharges are no longer automatic. When making recommendations to approve/disapprove such discharge requests, the commander takes into consideration what is in the best interest of both the servicemember, and the military service.
Sole Surviving Son/Daughter. Except during times of war, or national emergency, one can request a discharge if they are a "sole surviving son or daughter." This does not mean that they are an "only child," or that they are "sole surviving" because someone died in a traffic accident. In the military, a "sole surviving son or daughter" is one who is any son or daughter in a family whose parent or one or more sons or daughters served in the Armed Forces of the United States and
- Was killed in action.
- Died as a result of wounds, accident, or disease while serving in the U.S. Armed Forces.
- Is in a captured or missing-in-action status.
- Is permanently 100 percent physically disabled or 100 percent mentally disabled due to service connection.
Early Separation to Further Education. Aha! Thought you found that loophole, didn't you? Maybe, but maybe not. DoD Directives allow a military member to be discharged early to pursue their education if they are within 90 days of their normal separation date. Sometimes a service will approve an Educational Discharge Request of more than 90 days. For example, Air Force personnel can request separation after two years of service, if they have been accepted at an accredited school for medical training as physicians, dentists, osteopaths, veterinarians, optometrists, or clinical psychologists. The Navy Personnel Manual allows sailors to request a discharge for education in excess of 90 days, but the approval authority for a 90 day (or less) discharge is the commanding officer (special court-martial authority), and for discharges for more than 90 days before the normal separation date, it goes all the way up to the commander of the Navy Personnel Command. Neither thehe Army regulation (AR 635-200), nor the Marine Corps Regulation (MCO P1900-16F) allow for Educational Separations of more than 90 days prior to normal separation date.
Breach of "Guaranteed Job" Clause of Enlistment Contract. Here's another aspect where some people become confused. It's important that you understand what a "guaranteed job" is in the military. If you have a "guaranteed job" in your enlistment contract, it does not mean you will get that job, come Hell or high water. There may be reasons, after you enlist, that you can't get the job that your enlistment contract "guarantees." What happens in that case, depends on the situation.
In general, if you can't get the job due to something beyond your control (such as the service phased out the job, or downsized the job, or made a mistake and discovered that you don't qualify for the job, or you are denied a security clearance -- not due to giving false information), then you will be given the choice of applying for a discharge, or choosing a new job from a list of available jobs that you qualify for. In this case, the choice is yours (It should be noted that while these situations have been known to happen, they occur rarely).
On the other hand, if you fail to qualify for the job due to a reason within your control (you fail in training, you get into trouble, or you give false information on your security clearance application and are denied a security clearance), the choice is not yours. The military will decide whether to discharge you (throw you out), or to retain you and retrain you into a job that you qualify for. In this case it's the military's choice.
Early Release to Serve in the Active Guard or Reserves. Some of the services (such as the Air Force) allow personnel to request early separation to service in the National Guard or Active Reserves. However, in order to qualify, one must be within a designated time (usually one or two years) from their normal date of separation. Approval is certainly not automatic, and are based on the "needs of the service." In other words, if you're serving in a "shortage job," forget it.

