Recent research reveals that nutrition and environmental toxins significantly impact neurodevelopmental disorders like ADHD and autism. The critical window begins before conception, as both maternal and paternal health influence outcomes. Essential nutrients including folate, omega-3 fatty acids, and vitamin D support proper brain development, while environmental chemicals like BPA, phthalates, and heavy metals can disrupt these processes through hormone dysregulation and oxidative stress. Studies show that food-first approaches focusing on whole foods and the Mediterranean diet pattern may help mitigate risks. The Western diet, high in ultra-processed foods, contributes to inflammation and poor neurodevelopmental outcomes. Healthcare professionals should emphasize nutritional optimization and toxin reduction beginning in the preconception period, with supplementation considered only when dietary approaches are insufficient.

MTHFR gene variants affect 30-60% of the population and have significant implications for reproductive health. These common polymorphisms (677C>T and 1298A>C) reduce the enzyme's ability to convert folate into its active form, impacting critical methylation processes essential for fertility. Research shows these variants affect both male and female reproductive function through multiple pathways including elevated homocysteine levels, DNA methylation abnormalities, oxidative stress, and impaired neurotransmitter synthesis. For women, MTHFR variants can impact ovarian function, oocyte quality, implantation success, and pregnancy maintenance. In men, they're associated with compromised sperm parameters and DNA integrity. Evidence suggests that using active forms of folate (L-methylfolate) rather than synthetic folic acid may be more effective, with timing beginning 3-6 months before conception attempts for optimal outcomes.