Answer:
Not have sex or use condoms. Also, do not share needles or any other items that you stick into your skin.
Explanation:
For a family of four, a first aid kit would include scissors. A multi-purpose tool would come handy, but is not necessary. Rubbing alcohol is out of the ordinary, and barbiturates are a type of drug unneeded in a first aid kit.
All of them except condoms. Everything you take orally gives you hormones such as progesterone and estrogen to fool your body into thinking you’re pregnant so you won’t produce an egg that month. Other methods such as the ring and patch do the same, just not through direct ingestion.