This is wrong and will make more stutters ashamed of their condition when they don’t spontaneously get better. Some do but many don’t. That is a well known fact. If you are still stuttering in your teens, especially late teens, you most likely have a chronic condition that needs to be addressed. I say this as a 60-something who still stutters and knows many others who still wrestle with the damn affliction (we have that 6th sense that allows us to spot other stutters right away). In any case, it’s not the stutter itself that hurts you, but the psychological response, and it’s a natural response. Social isolation and ridicule is devastating. So lesson #1 is don’t treat others this way, so racism and sexism is out the door. All that said, how can you help yourself? Stutterers need to find a speech therapy approach that works for you. Each person is different do it might be different for you versus someone else. For me, HCRI (Hollins Communication) in Roanoke, VA, worked real well. It’s expensive, but they have scholarships. I did it more than 30 years ago. When I practice what they taught EVERY DAY, I can be pretty fluent. If I don’t? Well, I’m back on the tightrope (I am a moderate stutterer and can sometimes hide my condition, another curse, in a way). Some more severe stutterers did better than me coming out because they were wholly dependent on the techniques taught. I was jealous. Anyways, that’s all I have to offer. People that don’t grow out of it by their teens will never be a naturally fluent speaker, but with work they can become fluent with a reasonable amount of work and attention.