She fell in love with a Vespiform named Christopher in human guise in India in 1886. The relationship resulted in an out-of-wedlock pregnancy. Before the child could be born, Christopher was drowned in the monsoons of 1886 when the Jumna River overflowed its banks. Clemency returned to England and hid herself away in a locked room for the rest of her pregnancy, claiming it was because she'd had malaria.
She gave her half-human half-Vespiform infant son to an orphanage, and would not see him again until forty years later, by which time he was known as Reverend Arnold Golightly and had just discovered his Vespiform heritage.
Only Clemency's faithful servant, Miss Chandrakala, knew of her first pregnancy.
Clemency lost both of her children. Arnold killed his half-brother while in his Vespiform form and Donna Noble killed Arnold to save Agatha Christie when Arnold couldn't be reasoned with. (TV: The Unicorn and the Wasp)