What do you think is the least effective method of contraception and discuss why ?

The least effective method of contraception is typically considered to be natural methods, such as fertility awareness-based methods. These methods involve tracking your menstrual cycle and abstaining from sex or using a barrier method on the days you're most fertile.

The reason these methods are considered least effective is due to the high potential for error. They require a deep understanding of one's own body and menstrual cycle, as well as a high level of discipline to abstain from unprotected sex during fertile periods.

According to the Centers for Disease Control and Prevention (CDC), fertility awareness-based methods have a failure rate of 24%. This means that 24 out of 100 women will become pregnant in the first year of typical use. This is significantly higher than other methods such as hormonal contraception (like the pill or patch), intrauterine devices (IUDs), or barrier methods (like condoms), which have failure rates ranging from less than 1% to 13%.

It's important to note that effectiveness can vary greatly depending on how correctly and consistently a method is used. For example, condoms are 98% effective with perfect use, but with typical use (which can include incorrect application or forgetting to use one), their effectiveness drops to about 85%.

Finally, it's worth mentioning that no method of contraception (except for total abstinence) is 100% effective, and most methods do not protect against sexually transmitted infections (STIs). Therefore, it's important to consider both pregnancy prevention and STI protection when choosing a contraceptive method.