A man should not spill his seed on the ground

Dear Pastor,
I am a Christian man. I have been reading your column for many years, and I can say that I agree with many of the things you say. However, I am surprised that you do not condemn masturbation.
I know the Bible does not support masturbation. To my knowledge, it is condemned in Scripture. A man should not spill his seed on the ground. His seed is meant to generate life and not to be cast away.
Do you remember what happened to Onan? Onan spilled his seed on the ground because he did not want to impregnate a woman,and he was killed for doing so. Therefore, it is not right for a man to masturbate.
So, Pastor, I would like you to look at this matter again. A man should have as many children as possible. He should be grateful that he is able to do so and should not use condoms or do anything that would prevent him from impregnating a woman.
Just to remind you, the story is in the book of Genesis.
J.M

Dear J.M,
It is unfortunate that you think I am wrong for not condemning people who masturbate. By what you are saying, you seem to be unaware of the fact that women also masturbate and that there are some counsellors who believe that women masturbate just as frequently as men.
You raise the matter of Onan. You should read the account in Genesis 38:8-10 carefully. Under the Old Testament law, when a man died without having children, his brother was encouraged to take his deceased brother’s wife and raise children in his brother’s honour.
Onan knew the law. He was willing to have sexual relations with his deceased brother’s wife, but he was not willing to impregnate her; that is why he spilled his semen on the ground.
This account of Onan and what he did has nothing, absolutely nothing, to do with whether a man or woman masturbates. It is foolish to condemn me and support your argument based on the account of Onan and what he did.
Numerous women masturbate when they are alone, and men do the same. How could you use what Onan did to condemn masturbation? If you think through this matter carefully, you should recognise that what Onan practised was the withdrawal method, which many couples practise. Often, when the sex is pleasurable, men forget to withdraw.
I just want you to understand that people have been masturbating for centuries. It is practised not only by teenagers and adults, but even little children, especially boys, who find pleasure in touching their private parts unconsciously.
Pastor