Ellen White (1827-1915) was considered by some to be a true biblical prophet. She was a very influential Christian Evangelical leader who was instrumental in founding the Seventh-day Adventist Church.
This is from her book "A Solemn Appeal".
"If the practice [masturbation] is continued from the age of fifteen and upward, nature will protest against the abuse he has suffered, and continues to suffer, and will make them pay the penalty for the transgression of his laws, especially from the ages of thirty to forty-five, by numerous pains in the system, and various diseases, such as affection of the liver and lungs, neuralgia, rheumatism, affection of the spine, diseased kidneys, and cancerous tumors. Some of nature's fine machinery gives way, leaving a heavier task for the remaining to perform, which disorders nature's fine arrangement, and there is often a sudden breaking down of the constitution; and death is the result."
Females possess less vital force than the other sex, and are deprived very much of the bracing, invigorating air, by their in-door life. The result of self-abuse in them is seen in various diseases, such as catarrh, dropsy, headache, loss of memory and sight, great weakness in the back and loins, affections of the spine, and frequently, inward decay of the head. Cancerous humor, which would lie dormant in the system their lifetime, is inflamed, and commences its eating, destructive work. The mind is often utterly ruined, and insanity supervenes."
Wow. She sounds like a real party.