Fertility can be controlled by hormonal and non-hormonal methods of contraception. Oral contraceptives contain hormones that inhibit FSH production, so no eggs mature. An injection, implant or skin patch gives a slow release of progesterone. This inhibits the maturation and release of eggs for a number of months or years.
Barrier methods, such as condoms and diaphragms, prevent sperm reaching an egg. Unlike hormonal methods, condoms also reduce the risk of sexually transmitted infections. An intrauterine device prevents the implantation of an embryo, or it releases a hormone. Spermicidal agents kill or disable sperm.
Other options are to abstain from intercourse when an egg may be in the oviduct, or to use surgical methods of male and female sterilisation, which are usually intended to be permanent.
To evaluate a method, look at how reliable it is, its side effects, how long it lasts and whether it protects against infection. Science can give these facts, but choosing a method also depends on personal, social and ethical views. So questions about contraception cannot be answered by science alone.