In this paper, we present simulations of quantum point contacts (QPCs) formed in semiconductor heterostructures over which a metal split-gate has been deposited. Biasing the gates creates a quasi-1D channel (ie. a wire, or a QPC for very short channels) which separates the 2DEG into source and drain regions and through which current can flow. Besides the usual plateaus at integer multiples of G0= (2e2/h), more recent experiments on QPCs however have found additional non-integer plateaus, perhaps the most noteworthy being a ∼0.7 G0 conductance anomaly. Incorporating spin-density-functional theory (SDFT) into our calculations, we are able obtain similar anomalies in our simulations. Moreover, we find that these features can be correlated with the formation of a spin-dependent energy barrier structure.