Biology · Reproductive Health · NEET
NCERT clearly states that although all persons are vulnerable, the number of cases is reported to be very high in the age group of 15 to 24 years. This is the age of highest sexual activity and lowest awareness, so it is easy to remember and easy to test. If a question gives you an age band, 15-24 is the correct answer.
NCERT says all persons are vulnerable to these infections, so no one is fully safe. But some people have a much higher chance. So the correct framing is: everyone can get an STI, but risk is highest in the 15-24 age group and in people with multiple partners, unsafe blood, or shared needles.
NCERT lists four HIV transmission routes and then names the high-risk people: those with multiple partners, people who receive transfusion of contaminated blood or blood products, people who share infected needles (as in intravenous drug abusers), and infants born to an infected mother (through the placenta). These four also cover the main STI risk groups.
STIs spread mainly by sexual contact. Every new partner adds a chance of meeting an infected person, so having many partners or unknown partners raises the risk. That is exactly why NCERT's first prevention rule is: avoid sex with unknown or multiple partners.
The baby does not catch it by sex. An infected mother can pass HIV to the child through the placenta before birth (and some STIs during birth). So the newborn of an infected mother is a high-risk person even though the transmission is not sexual for the baby.
Sharing infected needles is a blood route, not a sexual one, but it still spreads HIV and hepatitis-B which are counted among STIs. That is why intravenous drug abusers who share needles are a named high-risk group even without sexual contact.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
15 to 24 years. NCERT states that though all persons are vulnerable, incidences are reported to be very high in this age group.
Individuals with multiple partners, those who receive contaminated blood or blood products, those who share infected needles (intravenous drug abusers), and infants born to an infected mother.
Yes. Multiple or unknown partners increase the chance of sexual contact with an infected person, so it is a key high-risk behaviour. Avoiding it is NCERT's first prevention step.
Yes. A baby born to an HIV-infected mother is at high risk because the virus can pass through the placenta from mother to child.
They have the highest sexual activity and often the least awareness and access to check-ups, so both exposure and late detection are more common in the 15-24 band.
