Looking for 90s book title - Pandemic cure causes sterility and children sex change. Plot: There is a pandemic. The cure causes selective sterility mother's must find fathers with different blood types to conceive a child. At puberty, males change to females or females change to males due to menstrual cycles.

  • Hi, welcome to SF&F! Do you have any recollection of what the cover looked like? Please check out the other suggestions for story-id questions and edit in any additional details you might recall. – DavidW Jul 21 '20 at 22:17
  • No sorry it was a paperback book purchased before 1995. I do not remember any cover details or the author. I remember a blood-type A mother went to a bar to find a blood-type O father. The child conceived was born male then suddenly at puberty changed to female over night. This child would eventually change back to being male if in the presence of a menstruating female. Eventually humanity changed to everyone was two-sexed. When female all of these 'new humans' could conceive a child regardless of the parent's blood-types. – Jesse Culton Jul 21 '20 at 22:23

This might be "The Breeds of Man" by F.M. Busby. With publication date of 1988, it more or less fits with your memory of a 90s book.

Scientists find a cure for AIDS, but a consequence is that women become infertile to a second pregnancy to men with the same blood type as the first. To fix this problem, the scientists create a second type of human, the Mark II, described on the cover blurb as "a remarkably adaptable breed of man able to survive when normal humans cannot". However, it is discovered that when they hit puberty the Mark IIs cycle between genders every month.

  • THANK YOU! It is indeed The Breeds of Man by Busby. – Jesse Culton Jul 22 '20 at 0:48
  • Glad to help! As you're certain it's correct, can you click to accept the answer? Thanks. – Clara Diaz Sanchez Jul 22 '20 at 9:14

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