. >> for 21-month-old lin jiahe, saturdays begins in with a menagerie of toys... ...under a shower of attention. >> little jiahe is an only child. he holds the most precious place in the household, with parents and grandparents catering to his every whim... and documenting his every move. >> "i am constantly writing to my son, telling him my thoughts and feelings in micro-blogs or postcards, which he will see in the future. i'm writing down the problems i have encountered and the way i have found to tackle them in the hope that they will be useful to my son when he grows up." >> jiahe and his parents are typical of the three-person nuclear family that has emerged in china in the last three decades, a result of the country's controversial family planning practice - commonly called the one-child policy. he yin and her husband lin zhongjie know just how it feels to be single children. they both grew up in one-child households, and they wonder if that's the best environment for their son. "one obvious feature of our generation is a strong sense of loneliness... most of us were growing gre

. >> but the biggest pressure might one day fall on lin jiahe, who may find himself caring for the entire family. >> "above all, he needs a good wife. then, in the future, when the population is ageing, it will be an inevitable trend to hire care services. also, i think there will be more jobs, professionals or relevant facilities to respond to this. perhaps the government or market will provide these services. it is bound to happen, a big responsibility that awaits china's youngest generation will come of age in an ever changing society. nerds. tonight sharks. we are tracking some of the misunderstood cret cite cret cre dry cre creatures in the sea. we are behind the wheel of the fruifuture testing out the drivs car. tonight police, science and a computer program may be able to predict crime before it happens. i am an ento entomologist. that surthat is our team and leo some science. ♪ hi guys an welcome to techknow. and rita rear going to start with you. your story combines two of the coolest things armed -- around. you mean robots and sharks. >> robots and sharks. >> this is the coolest