Hello. Thank you for writing to us The fact that you son is sexually active and has genital lesions, I suggest a possibility of an STD. It could be either Genital Warts, Molluscum Contagiosum or Genital Herpes. The reason these lesions are seen at base of shaft of penis is because he always uses a condom. A condom covers only shaft of the penis but leaves a lot of neighboring skin exposed for contact with infected genital secretions and infected genital surfaces. A condom protects only the covered portion and therefore these lesions at base. I suggest that he visits a dermatologist for a confirmatory diagnosis and appropriate treatment. Genital warts are skin colored, asymptomatic bumps; Molluscum lesions are pearly white, hard asymptomatic, bumps; whereas Genital herpes usually presents with painful sores/ erosions. Regards