Delays in your period can be caused by a variety of different things. Pregnancy is only one of these. You may of tested too early and if this is the case, I would recommend you perform a HPT 3 - 4 weeks after you last had unprotected sex. Alternatively see your Doctor for a Quantitative beta hcg pregnancy blood test which can be performed now. It is 100% accurate.
Entirely likely--about 50% of the population could definitely be expected to be able to claim this condition (males).
If you aren't having your period, and you should be having a period, you really ought to take that question and your body to an OB-GYN instead of Wiki Answers. There are a number of factors that could cause this. Among them are:
There are other causes but most of those involve illnesses such as cysts, tumours and cancers.
If your home pregnancy test is negative and your menstrual period is late it can be cause by a number of reasons. Stress, illness, change of diet, weight loss or gain, travel, and exercise can all cause changes to your menstrual cycle. It's best to wait a few days and retest if your period doesn't start or visit your doctor.
False negatives are far more common that false positives on home pregnancy tests. Make sure you are taking the test properly and are not using diluted urine.
No
Yes
No, a period and a negative HPT (used at the appropriate time) indicates no pregnancy.
. . . means that you arent pregnant.
Most pregnancy tests are 99%
No you can't be pregnant and still have your period. You can have a light bleed but not a period. As for the whole negative test thing, it could be a false negative.
Possibly the pregnancy test is ineffective. Try another one.
Who's pregnancy test? Yours?
You are pregnant
Unlikely - the bleeding probably was your period
Having your period means you aren't pregnant
Most pregnancy tests are accurate day one of your missed period, if your test is negative retake it in 3 to 7 days.