My 16-yr-old sister's too sexually active

I’m in my 20s and have recently discovered that my little sister is sleeping around  with old and young men in the neighbourhood.
She’s only 16.
I was shocked and ashamed of her waywardness. When I tried to talk to her, she scoffed and called me jealous. Do you think I should let my parents know?
Your wish to curb your little sister’s promiscuity is justified. She is physically and emotionally in danger.
Girls or young women who sleep around get hurt, and they always regret their behaviour. She is at risk not only of infection and unwanted pregnancy, but also of harming her self-esteem. A girl who is sexually easy, loses the respect of all men, and respect for herself.
There’s no need to involve your parents. Instead of attacking her behaviour, encourage her  to accept you as her sexual and emotional guide by talking through the practicalities of safe sex-including the consistent and careful use of condoms.
Discuss the way alcohol, drugs and peer pressure can lead to reckless sex, STIs, abortions, humiliation and self-hatred.
Above all, give her the affection, love and loyalty she’s obviously desperate to have.
(Bunmi Sofola)