The National Testing Agency (NTA) is responsible for NEET. You need to reach out to them to get your gender rectified on the scorecard.

You can also write a formal letter to NTA explaining the discrepancy and requesting a correction. Include your NEET roll number, registration number, and a copy of the scorecard with the highlighted error.

• Your Name: As mentioned in the application form.
  
  
• Your Contact Information: Email address and phone number.
  
  
• NEET Roll Number and Registration Number: For reference.
  
  
• Error Description: Clearly state that the gender on the scorecard is incorrect.
  
  
• Request for Correction: Politely request NTA to rectify the gender on the scorecard.
  
  
• Attach a copy of the scorecard: Highlight the gender error.
  
  Look for the official NTA address on their website or through a web search.You can send the letter by registered post for tracking purposes.
  
  https://medicine.careers360.com/articles/neet-last-minute-preparation-tips
  
  I hope it helps!