It has already been tweaked a bit. The Royal Family used to include only the male children of the eldest son of the Prince of Wales. If that rule still applied, only the son of the current Duke of Cambridge, George, would be a royal; his daughter Charlotte would not. The rules were tweaked in 2012 when the Duchess of Cambridge was pregnant with her first child.
I’m not sure whether they anticipate a more general elimination of gender discrimination. If they were to do that, the size of the royal family would be considerably increased - Princess Anne’s two children are the grandchildren of a monarch, and they both have spouses. Likewise Princess Margaret’s two children and their spouses would be included. Plus the living female-line grandchildren of George V, and their spouses.
I think there might be adverse public reaction to a substantial expansion of the Royal Family. Plus, there’s a possibility (to put it no higher) that the people affected are quite happy not being royal, and wouldn’t welcome the baggage that comes with the status.
While gender discrimination has been eliminated as regards succession to the throne, it certainly has not been eliminated generally with regard to royalty. Prince Andrew’s title as Duke of York will die with him, for example, since he has no male heir, and Prince Edward’s title of Earl of Wessex will descent to his younger child James rather than to his first-born Louise, who has the wrong chromosomes. There doesn’t seem to be any great appetite for change as regards these aspects of royalty, so I wouldn’t assume that there will be change in the way membership of the royal family is defined.