Losses on home loans chipped away at the earnings of mortgage insurer Genworth Financial in the March 2013 quarter.Genworth said, in its quarterly filing, that its loss ratio increased to 47 per cent, from 36 per cent, over the quarter.Net operating earnings in Australia were A$46 million, down from $62 million in the December 2012 quarter.New delinquencies increased seven per cent from the previous quarter, while insured loans returning to normal were down 24 per cent. Genworth said both shifts reflect normal seasonal variation.