From the Illinois Adoption Act (this is an excerpt, link at the bottom takes you to the full act) No exceptions noted for only one parent traveling to China or for special needs.
"(c) In the case of any foreign-born child brought to the United States
for adoption in this State, the following preadoption requirements
shall
be met:
(1) Documentation that the child is legally free for
adoption prior to entry into the United States shall be submitted.
(2) A medical report on the child, by authorized
medical personnel in the country of the child's origin, shall be
provided when such personnel are available.
(3) Verification that the adoptive family has been
licensed as a foster family home pursuant to the Child Care Act of
1969, as now or hereafter amended, shall be provided.
(4) A valid home study conducted by a licensed child
welfare agency that complies with guidelines established by the
United States Immigration and Naturalization Service at 8 CFR
204.4(d)(2)(i), as now or hereafter amended, shall be submitted. A home
study is considered valid if it contains:
(i) A factual evaluation of the financial,
physical, mental and moral capabilities of the prospective
parent or parents to rear and educate the child properly.
(ii) A detailed description of the living
accommodations where the prospective parent or parents
currently reside.
(iii) A detailed description of the living
accommodations in the United States where the child will
reside, if known.
(iv) A statement or attachment recommending the
proposed adoption signed by an official of the child welfare
agency which has conducted the home study.
750*ILCS*50/**Adoption Act.(c)