There are many scientific questions atheists mentions aginst SGGS. Howvwer SGGS also uses analogy & metaphor. People have a habit of taking everything literally without contemplating it, including some Sikhs these days who say earth is flat or sun & moon are lamps. SGGS is not a scientific book neither claims to be. I also disagree with Sikhs who often write article about how 'Sikhi Is Scientific', we do not need any scientific approval for Gurbani. I am covering here only 3 such questions. 1.) Sikhi says there are 8.4 million species. However Science says there are approx. 8.7 million. ans. It depends on classification. If we reach the level of Spritually wise men, we will find out how & why they classified it. Gurbani mentions 4.2 mllion in water so rest must be on land. This number is older than Sikhi and was mentioned by Hindu Sages. Now they weren't travelling around the world but still gave a strict number & Gurus agreed with them. 2.) Sikhi mentions 4 forms of births i.e. Womb, Egg, Ground, Sweat. However Sweat doesn't give birth. ans. Yes sweat doesn't give birth on its own. But you are not under the ground, nobody is mating on your skin & nobody layed eggs on you. So sweat creates an environment on your body for microbes and bacterias. 3.) Sikhi says Humans are born out of 'Rakt-Bind' i.e. Blood & Semen. However its not Blood & Semen but Egg & Sperm which are necessary. ans. I will mention four reasons for such statement by Gurus: * Again Classification. Blood and Semen are first step in creation. Blood is the first part of monthly cycle for women but men have no cycle, so Semen is used as a super set. * It is said that because a woman is not having periods while pregnant, she is using her blood to 'plough her child'. This is more of a philosophical reason to glorify Mothers. * People at that time considered periods as something bad which makes women spritually dirty so Gurus highlighted the importance of Blood. * It was simply a terminology of that time. If you read Sidh-Gosht, Siddhas also used the same term while questioning Guru Nanak.