Has Horizon (BBC Two) taken some kind of happy pill? Last week we had the heartwarming tale of an autistic woman who became a leader in the field of animal behaviour. Last night we got the story of Robert Graham, a millionaire amateur geneticist, in a documentary that enjoyed the more absurd aspects of his endeavours. It showed that history repeats itself, first as tragedy, then as farce. The eugenic dreams of the geneticist J. B. S Haldane became the Nazi nightmare, but astonishingly there were people like Graham still fantasising that they could breed better humans.

Graham was a retired optician who had made his fortune by inventing shatterproof plastic lenses. In 1980 he launched his “genius sperm bank” in California — where else? — with donations from Nobel laureates. He wanted to stop what he saw as the degrading of America’s gene pool by “morons” by offering women the chance to have gifted children — if they happened to be married, white and of a certain intelligence. Although Graham was branded a racist, fascist and buffoon at the time, Horizon saw him as more well-meaning than misguided.

No baby was born from Nobel sperm as Graham’s initial concept had a fundamental flaw; by the time the Nobel committee gets to honour someone, his sperm’s best-before date is usually a distant memory. Graham had managed to recruit only three Nobel winners anyway, including the physicist William Shockley, a proponent of near-Nazi views on race and eugenics; the other two quit to avoid the kind of notoriety that attached itself to Graham’s Repository of Germinal Choice.

The first couple to withdraw successfully from the bank turned out to be convicted felons. Yet women still applied enthusiastically, apparently because Graham had handpicked, so to speak, his investors. He would target scientific conferences, wine and dine various PhDs, then invite them back to his hotel rooms to make a donation. “It was weird, almost like being on a date,” recalled one donor. “I guess I’ve spent my whole life in sperm,” said a cryogenic expert with a straight face as he recalled teaching Graham how to freeze sperm in liquid nitrogen; you suspect he’s now freezing billionaires awaiting some needed cure.

In often using reconstructions and Graham’s own words delivered by a Werther’s Original grandfather type, this was a surprisingly jaunty account; it even ended with Monty Python’s Every Sperm is Sacred. But it got awkward when Graham began narrating his own death in 1997, drowning in a hotel bath after a heart attack. And in mostly having interviewees who were satisfied customers, we were left with too many unanswered questions.

Few, if any, of the 217 children produced by the bank over its 19-year existence have turned out to be geniuses. Many seem to be above average academically, but could that be more to do with pushy mothers who wanted “genius babies” in the first place? Did husbands struggle to love children who were not their own? Did the donors want to find their offspring and vice versa?

Now I don’t want Horizon to return to the days when all we got were talking heads sporting ZZ Top beards and looking as if they’d played Dark Side of the Moon once too often. But one expects the series to offer a more rigorous examination of its subjects. Even when it scared us every other week with apocalyptic scenarios involving killer bugs or space rocks the size of Wales, it tended to cover all the angles. So give me old Horizon’s doom and gloom rather than its cuddly new version if that means we get back some analytical grit.

More observational than analytical was My New Home (Channel 4), the first in an annual series over the next five years that will follow how three new immigrants, all now 11, adjust and assimilate into their new lives in Britain. Boisterous, PlayStation- obsessed Marshal from Zimbabwe has moved to Tyneside. Cheeky Imran has come to Peterborough from rural Pakistan and is in a school of 1,000 pupils speaking 30 languages. Thoughtful Altynay from Kyrgyzstan now lives in a Yorkshire village.

Hopping between each child made for scrappy viewing at times but it caught some sense of the disorientation that these not-yet- streetwise kids must be feeling. As Altynay became an object of curiosity in the playground, I was reminded of the documentary Windrush, which had shown how arrivals from the West Indies had experienced a relatively benign attitude towards them until their novelty wore off. This is a series that can only develop in depth as it progresses. Let’s hope the latest run of Horizon does the same.

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