The sexual revolution of the 1960s brought challenging issues for the Church. Pope Paul VI's 1968 encyclical Humanae Vitae reaffirmed the Catholic Church's traditional view of marriage and marital relations and asserted a continued proscription of artificial birth control. In addition, the encyclical reaffirmed the sanctity of life from conception to natural death and asserted a continued condemnation of both abortion and euthanasia as grave sins which were equivalent to murder.[255][256]