[3][15][16] Moalem was the first to propose that the progressive neurodegeneration associated with dementia and Alzheimer's disease might be caused or exacerbated by an excessive amount of the metal iron in the brain.

[23] In this capacity, Moalem worked in HIV prevention for the Population and Community Development Association (PDA) and was responsible for the operations of the Tarn Nam Jai HIV+ Orphanage in Bangkok, Thailand.

His clinical research also led to the description of an SRY negative type of XX male sex reversal that resulted from a duplication of the SOX3 gene found on the X chromosome.

[27][20] In March 2014, Moalem and his team won a hackathon at MIT to build a smartphone app that can be used to treat patients by identifying predispositions to certain diseases based on facial structure.

[3] He is a frequent keynote speaker on the topics of genetics, human sex differentiation and its medical implications, pandemics, evolution, antimicrobial resistance, iron metabolism, botany, entomology, personalized medicine and has appeared and been interviewed by CNN's Christiane Amanpour, NBC's Today Show, BBC Radio 4, Bloomberg Television, Comedy Central's The Daily Show with Jon Stewart, CBS This Morning, Good Morning America and NPR.

The book, co-written by Jonathan Prince, lays out eight case studies revolving around the argument that common hereditary diseases exist because at one point they were an adaptive advantage for our ancestors.

[41][42] The book, co-written by journalist Matthew D. LaPlante, unpacks emerging research into the flexible genome, which is "mediated and orchestrated by how you live, where you live, the stresses you face, and the things you consume," promising a future in which people will make health decisions not based on what is good for most of the people most of the time, but rather what is genetically best for each individual based on their specific genetic and epigenetic profile.

[44][45] [46][47] In the book Moalem proposes the Law of Homogameity as the explanation for the biological survival advantage which occurs across the tree of life when a species inherits two of the same sex chromosomes.

[50] Moalem's assertion regarding the female survival advantage became apparent during the COVID-19 pandemic, where males were found to have a higher mortality rate reported across many age groups.