People of Paradise will be purified from every wrong thinking, wrong desire or wrong temptation. They will never think about doing any wrong. Changing gender will never be wished by any one in Paradise. Allah said in Quran about people of Paradise ( And We removed away from their chests every bed feeling) A-A'raaf, 43.
'Changing gender is mentioned in Quran as one of the Satanic aims.( Verily, I will mislead them, and I will arouse in them false desires, and will order them to slit the ears of the cattle and will order them to change the nature created by Allah). (Sura An-Nisar', 119).
Wassalam.