I am a male MS4 applying for Ob/Gyn residence...here is my experience...
In general, female patients (particularly the younger generation) tend to gravitate towards female physicians. However!, over the last 2 years on L&D, the benign Gyn service, and the Gyn Oncology service I have only had a handful of patients request to see a female med student/physician instead of me. This largely depends on your motivation, your interest, and your programs motivation to back you up and help get you involved. I have had nurses in the past (particularly during 3rd year) that have not allowed me to see "their" patients because I was male. I try to stay away from these nurses, but if all else fails tell your superiors and they will certainly remedy the matter. Also, nurses tend to get you more involved when they know that you are truly interested (which has been the case during my 4th year electives where I have worked with nurses that didn't let me do anything as a 3rd year). Just make it known early that this is something you want to do. I have also had patients that have requested to see female providers. Although we try to accomodate their requests, if no female providers are available...guess what?...they are going to get me or a male resident whether they like it or not or they could just wait a few hours until a female becomes available. You have to remember that you are training at a teaching hospital. Patients are aware of this...and they usually have to sign a form to this effect...and know that they will likely see both male and female med students and residents.
I remember the task I feared most during 3rd year was performing a sterile-speculum exam (SSE). I felt that I was all thumbs, couldn't find the cervix, and was truly hurting my patients. Although, SSE is more uncomfortable than I will ever understand the key is be confident and realize that you have a job to do. If you walk in the room shaking and scared sh*tless the patient's perception of the discomfort will be magnified and both you and her will leave feeling horrible.
With regards to the field of Ob/Gyn there is most definitely a place for a male. I have heard and experienced on the interview trail first-hand that the Y chromosome contains unspeakable powers and getting you into an excellent Ob/Gyn program.

Furthermore, there are subspecialty fields (such as Gyn Oncology) that are male-dominated (although, like everything else, there is a shift towards equilibrium). So do not worry. You should not feel guilty about being a male Ob/Gyn...just remember you are not alone, a few decades ago almost all Ob/Gyn's were male. You will be a desirable residency applicant and you will find a job after residency regardless of what others may say.
Sorry for the dissertation....
PM me if you have any thoughts or questions
Good luck with everything.