{ 1 } - When properly practiced, it can be as effective as any method except sterilization and does not have the obvious disadvantages of a sterilizing procedure?
{ 2 } - It is in harmony with the present day mechanistic tendencies of our society.
{ 3 } - Unlike other comparably effective methods, namely, progesterones and intrauterine devices, it has no medical risks.
{ 4 } - It is never abortifacient, as progesterones and intrauterine devices almost certainly are.
{ 5 } - It is inexpensive, does not require regular medical checkups to avoid side effects, and can be effectively taught by simple practical instruction.

On the contrary, it does not rely for its value simply on statistical effectiveness (though it is as effective as any method except sterilization) but on the increased intimacy and love between the couple. See p. 301.