Del. Code Ann. tit. 16, § 3016F
(a) Except as provided in subsection (b) of this section, cats and dogs must be spayed or neutered and inoculated for rabies, or have a valid exemption from vaccination under § 8204 of Title 3, prior to adoption from any of the following:
(b) Following a medical examination, if a veterinarian determines that an animal cannot safely or humanely undergo a spay/neuter procedure, the animal shall be exempt from the spay/neuter requirement.
75 Del. Laws, c. 326, § 1; 79 Del. Laws, c. 377, § 2; 81 Del. Laws, c. 224, § 2; 84 Del. Laws, c. 477, § 1