Leicester Tigers and England scrum-half made the announcement on Saturday evening
England and Leicester Tigers scrum-half Ben Youngs has ruled himself out of the upcoming Lions Tour of New Zealand for family reasons.
Youngs, 27, was one of three scrum-halves selected to go to New Zealand as part of the 41-man squad and on Saturday evening announced that he would not be available.
The wife of Youngs' brother, Tom, has been battling cancer for three years and the family have received the news that her illness is now terminal.
"We are a very close family and, as I am sure everyone can respect, time is now precious together," Youngs said in a statement on the Leicester Tigers website.
"The most important thing for me at this difficult time is to be able to offer as much support as I can to Tom and his family in the remaining time we all have together.
"It is a great honour to be selected as a member of the British & Irish Lions squad and I would like to thank Warren Gatland, the staff and the other players for their understanding in this situation.
"I wish them well and, like all rugby supporters in British and Ireland, hope they have a successful tour."
He will play the Tigers until the end of the Aviva Premiership season.
Lions head coach Warren Gatland said: "We fully understand and respect Ben's decision to stay at home.
"Family comes first and I know from having toured with Tom and Ben in 2013 how close they are. This is a difficult and important time for them and we send Ben, Tom and their family our heartfelt thoughts."
Scotland and Gloucester Rugby scrum-half Greig Laidlaw will join the squad in his place.