They say that the heart wants what the heart wants, but a recent study published in Nature suggests that genetic coding and body odour may play a key role in finding Mr and Mrs Right. If you thought love at first sight was real, or falling for your SO because of the way they looked was the reason you found your soul mate, guess again. It’s actually the result of a protein marker called human leukocyte antigen (HLA). Your immune system uses HLA to differentiate between your own cells and viruses and bacteria. But studies show they play a very important role in how you fall in love. Scientists have conducted studies on 254 couples to figure out how HLA affects sexuality, and the results were mind boggling. HLA system is a gene complex encoding the major histocompatibility complex proteins in humans. These cell-surface proteins are responsible for the regulation of the immune system in humans. The HLA gene complex resides on a 3Mbp stretch within chromosome 6p21. HLA genes are highly polymorphic, which means that they have many different alleles, allowing them to fine-tune the adaptive immune system. The proteins encoded by certain genes are also known as antigens, as a result of their historic discovery as factors in organ transplants.