“A Blessed Child” concerns the mingled fates of three sisters — Erika, Laura and Molly — who are the daughters, by three different women, of Isak Lovenstad, a renowned gynecologist who in his old age lives alone on a tiny Swedish island called Hammarso, which bears at least a passing resemblance to Faro, the island where Bergman lived for much of his life and where he died in 2007. Lovenstad’s claim to fame is his pioneering work in gynecological ultrasound: a technology with the uncanny ability to see deep inside women, into places they can’t see themselves. Larger than life, endlessly seductive, willful and blind as Lear to many of his own faults, Isak seems to his daughters to be immortal. “In the winter,” Ullmann writes, “he let his hair grow free, giving him an aspect of towering grayish white, which in combination with his handsomely lined, aging face suggested the beginnings of a rauk, one of those 400-million-year-old ­island outcroppings in the sea, so characteristic of Hammarso.”