Gender: boy
There were two matches for H. Wajchendler who were born between the years 1921 and 1927.
The first name was JOSEF HERSZ WAJCHENDLER born 23 July 1924 and he lived at RAUCH 31 flat 8 and RAUCH 31. He was deported with Transport 13 on 15/03/1942.
The second name I found was JAKUB HERSZ WAJCHENDLER born 3 July 1927 and he lived at RAUCH 31 flat 54 and SCHARNH (Scharhörnstrasse) 29. He changed addresses on 18.2.42 to Blech 30.
Either boys could be a match due to the fact they were born in the correct age range and they could have went by their middle names.