Actually the US. It has to be applied for if the child is born outside the USA with a non US Parent, and the US Parent has to meet several requirements such as having lived in the USA for 5 years after the age of 14.
If was total frustration on my part dealing with US Embassy in Bangkok to get my daughter US Citizenship, it took over 3 months. They basically required a DNA test to prove I was the real father and then proof that I met the US residency requirements.
https://www.uscis.gov/us-citizenship/citizenship-through-parents
Again, which country forbids (prevents) a parent from passing citizenship to their child at birth?