Final answer:
The statement is false; self-examinations can help detect some STIs with visible symptoms but are not as effective as medical tests for diagnosis, and while condoms reduce STI transmission risk, they do not guarantee complete prevention.
Step-by-step explanation:
The statement that self-examinations are not effective in the detection of STIs and are only effective in the detection of cancer is false. Self-examinations are indeed important for the detection of certain types of cancer, such as monthly breast self-exams for women and testicular self-exams for men to check for unusual lumps or changes.
However, while self-examinations might not be effective for diagnosing most STIs, they can sometimes help in identifying visible symptoms of some STIs like genital warts or herpes. Nonetheless, many STIs, such as chlamydia and gonorrhea, often go unnoticed because they do not cause symptoms, or the symptoms are very mild, thus a medical test is required for accurate diagnosis.
Regarding condom use, although they significantly reduce the risk of transmission, the proper use of condoms cannot completely prevent the transmission of all STIs due to the possibility of contact with infected skin outside the coverage area of the condom.