However, when the preterm infants were divided into two groups by gestational age and three groups by birth weight, we found that, for the NOS3 gene, the GG genotype and G allele increased while the GT genotype and T allele decreased, and infants with the GG genotype and G allele of NOS3 were less likely to have development of RDS in the 26–32.9 weeks of gestational age subgroup and the birth weight <1.5 Kg subgroup. The gene discussed is NOS3; the disease is newborn respiratory distress syndrome.