OK, Monkeys, typewriters and time. That's what we need. Isaac Asimov estimated that there are 135x10 to the 165th power(135 followed by 165 zeroes) possible chemical combinations for Hemoglobin. If we took all the atoms in the observable universe (generally accepted as 10 to the 78th power, but let's round it up to 10 to the 100th power to make the math easier.) and used them to try to make hemoglobin, recombining them once each second for the supposed age of the universe, (10 billion years or 3x10 to the 17th power), we just would not have enough time. That would consume about 10 sextillion universes worth of atoms every second. Even then it would take ten trillion trillion years to come up with all the different possible combinations of the atoms in Hemoglobin. With only 10 billion years to play with, we would be trillions of years short.
The DNA of the smallist known virus has 10 to the 1,505 power combinations. Do the math. As you can see, there isn't any way that it just happened. Some may point to the experiments that produced different amino acids but the odds on producing these acids is only about 40,000 to one. We can boil some chemicals and produce this relatively quickly. 10 to the 165th power is quite another matter. Remember, with each zero added the number becomes ten times bigger!
Enough monkeys, enough time, and enough typwriters may produce Shakespeare but 20 monkeys, 20 typwriters, and 20 years only produces a lot of monkey droppings!