The record to create this person was entirely mis-indexed. The record, indexed as a female named Katharine, is actually for a male that already belongs to this family. She simply does not, nor ever has, existed. Can she be removed?
Yes, if you are completely confident this is a badly created record for the other male and have the original record image the index was based on so that you can see the error made in the index, then just change her sex to male and merge the two records without bringing over any information. Then in the indexed source put an extensive note as to the situation:
Also put an extensive reason statement when you merge so that the correctness of what you did is immediately obvious to anyone coming across the merge in the Change Log.
If the above image does not come back, here it is again:
If possible, it would be good to correct the indexing if the source has an Edit button on it.