61.   The pandas are not old enough to produce offspring, but zoo officials are hoping they will mate in a few years.

62.   The pandas are not old enough to produce offspring, but zoo officials are hoping they eventually will mat.

63.   The pandas are not yet old enough to produce offspring, but zoo officials are hoping they will mate in a few years.

64.   The pests had been eradicated by introducing sterile male screwworms, which mate with female screwworms but fail to produce offspring.

65.   The pandas are not old enough to produce offspring, but zoo officials are hoping they eventually will mate.

66.   This means the brothers and sisters can be reliably mated to produce offspring with special genetic characteristics.

67.   Three previous cases of artificial insemination at Ueno produced offspring, although one died within three days of birth.

68.   Well, envy no more for in this game you have to breed mutant animals to produce pure offspring.

69.   When they mate with the native population of screwworm flies, no offspring are produced.

70.   Zoo officials are hoping he will mate and produce offspring.