An ideal contraceptive should have the following characteristics:

• Safe
• Effective
• Acceptable
• Inexpensive
• Reversible
• Simple to administer
• Independent of coitus

In addition, other characteristics that are commonly mentioned in the search results include:

• User-friendly
• Easily available
• No or least side effects
• No way to interfere with the sexual drive, desire and/or the sexual experience

Therefore, an ideal contraceptive should be safe, effective, acceptable, inexpensive, reversible, simple to administer, independent of coitus, user-friendly, easily available, have no or least side effects, and not interfere with the sexual drive, desire, and/or the sexual experience.