She said the move was an example of how the concept of motherhood has ‘been deconstructed’ – before going on to criticise the process of IVF.
Sir Elton is listed as the father and Furnish as the mother on the documents for their sons Zachary, four, and Elijah, two.
Both children were born to the same California-based surrogate mother – who the couple said they love ‘like a sister’ – and both share the same anonymous egg donor.
She is the latest celebrity to voice disapproval of Sir Elton, 68, and Furnish, 52.
Sir Elton was recently embroiled in a high-profile row with Italian fashion designers Domenico Dolce and Stefano Gabbana who called their IVF children ‘synthetic’.