Here is a very interesting post from the blog of Fr Hunwicke, Priest-in-Charge of the Anglo-Catholic church of S. Thomas the Martyr, Oxford. His subject is the perennial Christian teaching on matters of sexual morality.
It is a wide-ranging essay, considering among other things the issues of homosexuality and contraception. On the latter topic he writes about the Lambeth Conference decision of 1930, and the events leading up to the publication of Humanae Vitae. The article is well worth reading.