Why did you wife not allowed u to neuter the kittens?? Tell her, once the kitten sexually mature,expect the female cat to give birth every 4 mths.Each pregrancy estimately can produce 4-6 kittens x with 4 pregrancy a year.Do your maths.We have more than enough unwanted kitten/cat strays on the street already. Don't add that into the statistic. Cats are not human that u can give them pregrancy planning pill whatsoever.Better neuter them before it's too late.