There are 10 words that start with 'congen'.
| congener | congeners | 
| congenial | congeneric | 
| congenital | congenerous | 
| congenially | congeniality | 
| congenitally | congenialities | 
Note: These 10 words that start with 'congen' are found from the USA & Canada version of the tournament Scrabble word list.