Bottom of stairs gate

My 2 year old has decided he loves to race up the stairs. Obviously not safe. We have a gate at the top so he doesnt fall down...but now we need a gate for the bottom. The ones we have dont fit across the bottom or screw into the sides...we dont want to screw into our wood finishes...any recommendations for a gate for downstairs that wont ruin the wood and can be left up/walked through? We have another baby coming in 5 weeks and I dont want to have to completely have to remove a gate all of the time.