The incidence of cancer among young people aged 15-39 has increased by 40% from 1975 to now. The author, who was diagnosed with stage 3 rectal cancer at age 35, shares their personal experience and insights. The reasons behind this sharp rise are unclear, but diet, inactivity, poor sleep schedules, environmental toxins, and increased height have been suggested as contributing factors.Eight of the 14 cancers increasing among young people are related to the digestive tract, which may be linked to dietary changes over the past few decades. Other potential causes include a shift in exposure to chemicals, pollution, and microplastics compared to previous generations.The author notes that screening has increased, but this cannot fully account for the rapid rise in cancers among young people. Many of these cancers are preventable, and addressing environmental factors could be key to reversing the trend.Research is crucial to understanding the causes of this increase, and individual actions like healthy diet and lifestyle choices can also make a difference. However, the author emphasizes that infrastructure changes, such as making cities more walkable or accessible to fresh foods, are necessary for a broader societal shift.(Note: The original text appears to be from an article or blog post, so I've kept the formatting and paragraph structure similar.)