How should I treat parents who show partiality between a daughter and a son?

I am a 20-year-old boy, and I have a 23-year-old sister. My sister is dominant, aggressive, and outspoken, whereas I am calm, silent, and reserved. My parents provide her with every medical facility, spending money, new vehicles, and other comforts, but they do not show the same care toward me. They only expect me to work hard, earn money, and support them in the future.

For example, my gums and teeth have become badly damaged (swallowed and receded) , yet they showed no concern for my health. However, just 2–3 days ago, they got braces installed for my sister. They have taken her to a dermatologist for skin fairness treatments, hair loss, and hair thickening. Even when she had a small scar on her hand, they immediately took her to a dermatologist. Meanwhile, my face has been badly affected by acne since I was 16 years old, I suffer from hair loss, and I also have acanthosis nigricans (darkening of the skin caused by insulin resistance). In addition, I experience sharp pain in my right shoulder. Despite all this, they still force me to work, and if I fail to do something, they verbally abuse me badly.

I am only 20 years old, and marriage is still far away for me. Yet my sister often insults and speaks vulgarly about the unknown woman who may become my future spouse and even about her family. My parents never stop her, and if I raise my voice in response, they silence me instead.

In the past two years, my parents have given my sister three mobile phones and one laptop. But whenever I ask for something, they either insult me, make me feel guilty, or force me to return the money. She is given preference in every important matter, whether it is selecting plots for purchase or making family decisions, while whatever remains is left for me.

I am seriously in pain.

How should I treat parents who show partiality between a daughter and a son?

I am a 20-year-old boy, and I have a 23-year-old sister. My sister is dominant, aggressive, and outspoken, whereas I am calm, silent, and reserved. My parents provide her with every medical facility, spending money, new vehicles, and other comforts, but they do not show the same care toward me. They only expect me to work hard, earn money, and support them in the future.

For example, my gums and teeth have become badly damaged, yet they showed no concern for my health. However, just 2–3 days ago, they got braces installed for my sister. They have taken her to a dermatologist for skin fairness treatments, hair loss, and hair thickening. Even when she had a small scar on her hand, they immediately took her to a dermatologist. Meanwhile, my face has been badly affected by acne since I was 16 years old, I suffer from hair loss, and I also have acanthosis nigricans (darkening of the skin caused by insulin resistance). In addition, I experience sharp pain in my right shoulder. Despite all this, they still force me to work, and if I fail to do something, they verbally abuse me badly.

I am only 20 years old, and marriage is still far away for me. Yet my sister often insults and speaks vulgarly about the unknown woman who may become my future spouse and even about her family. My parents never stop her, and if I raise my voice in response, they silence me instead.

In the past two years, my parents have given my sister three mobile phones and one laptop. But whenever I ask for something, they either insult me, make me feel guilty, or force me to return the money. She is given preference in every important matter, whether it is selecting plots for purchase or making family decisions, while whatever remains is left for me.

I am seriously in pain.