Although other interest groups are trying to appropriate the rainbow as a symbol of their cause it remains what God gave as a reminder of His promise to us, His wonderful covenant between Himself, mankind and all living creatures!
Genesis 9:12  Then God said, "I am giving you a sign of my covenant with you and with all living creatures, for all generations to come.  I have placed my rainbow in the clouds. It is the sign of my covenant with you and with all the earth.  When I send clouds over the earth, the rainbow will appear in the clouds,  and I will remember my covenant with you and with all living creatures. Never again will the floodwaters destroy all life.  When I see the rainbow in the clouds, I will remember the eternal covenant between God and every living creature on earth."  Then God said to Noah, "Yes, this rainbow is the sign of the covenant I am confirming with all the creatures on earth."
God has clearly spelled out His promises through the sacrifice of Jesus Christ His Son offers all mankind a better future. What's your response to His promise and offer?