Leave them where she found them. In almost all states, 18 is over the age of consent. And if she is going to be sexually active, at least she's smart enough to be using both Birth Control and condoms.
Also, birth control doesnt necessarily mean she is having sex. Many people take it for medical reasons or even to reduce acne or cramps. No need to jump to conclusions. If you are really bothered by this, you might want to talk to a parent or your sister about it.
Latex condoms (male) Polyurethane condoms (female condom)
Condoms.
Birth control only protects against pregnancy. Condoms protect against sexually transmitted diseases.
Condoms, female condoms, spermicide, the sponge, foam, or IUD.
Condoms.
Diaphragms, condoms, and the cervical cap are barrier methods of contraception.
By the Pharmacy and the medications, like birth control
There are many birth control methods aside from traditional birth control pills. Some of those include: Condoms, IUD, Nuva Ring, Depo-Provera, FemCap, Diaphram, and Female Condoms.
You could take Birth Control pills.
by using condoms or other birth control
Yes, if necessary for birth control reasons.
CONDOMS