From Ryanair's Conditions if Carriage
3.1.1 We will provide carriage only to the Passenger named in the Ticket. You will be required to produce valid travel documentation.
If that person arrives at the check in, with a valid ID card or passport that states only 1st and 2nd name, who are Ryanair to challenge whether that person describes themselves as Mr or Mrs on the ticket, since the names exactly match the travel document?
PS: no point asking for facts, as there are n't any, only opinions.