Sexual orientation is not a choice. People do not choose to be heterosexual or straight, they just are and the same holds true with 2SLGBTQ+ people. Gender identity is not a choice either - it is our authentic self. It is not something that can be changed. If you are a parent, choose to be proud that your child has figured out who they are and feels safe to share that with you. While nothing you did as a parent 'made' your child 2SLGBTQ+, how you respond will have a long-lasting impact on the quality of their life and your relationship moving forward.
Having a 2SLGBTQ+ child is not a reflection of your parenting skills. Having a child who feels that they can come to you and be accepted and loved when they tell you something that is not always accepted in society is a reflection of your parenting skills.