It was Father's Day during the weekend, a time that made me deeply miss my loving father who passed away nearly five years ago.

It is also a time that my daughter said "thank you" to me.

I told my daughter, who also celebrated her 20th birthday this weekend, how happy I am to have her as my daughter. Like all proud fathers, I talk endlessly about her.

Yet I feel this column should be devoted to Emily, who is celebrating her graduation this week from Edina High School in Minneapolis, Minnesota, and her mother, Kathryn, who has raised her the past 16 years after adopting her from a Chinese orphanage in Hefei, Anhui province.

I first met them 13 years ago in a park in Twin Cities and have seen them many times during their visits to San Francisco, where I was living in the Bay Area. I also flew to San Diego, California, to join their family tour of the great zoo and aquarium.

We met at least three times when Kathryn came to China to adopt the second, third and fourth daughter, or when the family came to visit the orphanage in Tonglu, Zhejiang province, where the second daughter Lulu was adopted. It was quite a surprise to me, since adoptive Chinese parents usually would not want to talk much to their children about their births, let alone go on a trip to trace their origins.

Every time we met, I saw the girls growing up happier and smarter. I have also received photos, postcards, letters and e-mails from Kathryn about the girls their Chinese language and dancing lessons, Chinese pipa instrument, piano and flute classes as well as their trips to Paris.

Emily has occasionally left me messages on my Facebook page, of which I apologetically have not been regularly using.

I have known a dozen Americans who have adopted Chinese children. But Kathryn is the one that I found a bit hard to understand for a long while. A single mother, she has adopted four Chinese girls, a task that seems too daunting.

The love and passion for the girls have cost her opportunities to find a life partner simply because many men feel awed at the demands of raising four daughters.

For Kathryn, being able to parent the girls and change their lives is the highest goal in life. It is the thing that keeps her happy and fulfilled.

"My children are the most important and worthwhile things in my life. They are beautiful treasures and I have been blessed to be able to parent them," she said.

Kathryn is by no means rich, not even compared to many middle-class Chinese these days. She had to juggle two jobs, mostly teaching in schools or working for adopting agencies, to raise the children.

She is a mother. She is also a father - and she deserves to be congratulated for a well-deserved Father's Day.

I am not sure if she knows that there is a Sons' and Daughters' Day on Aug 11, when she can celebrate the happiness brought about by the girls.

Whether it is Father's Day, Mother's Day or Sons' and Daughters' Day, it is a time to celebrate the love and happiness in life and family. This is certainly not limited to blood ties.

Congratulations, Emily, on your high school graduation. You are a wonderful daughter and elder sister.

Congratulations, Kathryn, for being a loving mom and dad and for changing the lives of four Chinese girls.

The author is deputy editor of China Daily US edition. He can be reached at chenweihua@chinadaily.com.cn