It is really unfortunate to know that your son affected by HPV. As human papillomavirus infection is the common STI;ie.sexually transmitted infection. As this infection is caused during sexual intercourse and even in many cases people don’t know the reason. If we talk about HPV in medical terms then there are more than 40 types of HPV infections present in male and female. These HPV type affect the genital area of female as well as of male. In many cases it is found that HPV type also causes in mouth and in throat as well. It is also found that people who are affected by this infection are unaware by this disease as they don’t know that they are having this disease as this disease does not show the symptoms. As HPV is sexually transmitted diseases therefore chances of getting this disease is more during sexual contact which get transfer from one partner to another. To get prevention it is advisable to get safe sex or use condoms. As in your case let me clear you that this disease is not transmitted through hug or by a kiss in cheek. Take Care.