Artificial intelligence in the Mass Effect universe does not mimic humanity like Fallout 4’s synths. Instead, the Geth are another alien race, just a synthetic one, created by the Quarians. In the Mass Effect universe, consciousness has multiple realisability: it's realised in humans, the mono-gendered Asari, the jellyfish-like Hanar, the dual-hearted Krogan and — if you believe that a machine can be conscious — the robotic Geth.
Source: wiktionary