Same-sex marriage

===Parenting===
{{Main|LGBT parenting|Same-sex marriage and the family}}
[[File:P051702-149695.jpg|thumb|Gay couple with a child]]
Scientific literature indicates that parents' financial, psychological and physical well-being is enhanced by marriage and that children benefit from being raised by two parents within a legally recognized union (either a mixed-sex or same-sex union). As a result, professional scientific associations have argued for same-sex marriage to be legally recognized as it will be beneficial to the children of same-sex parents or carers.<ref name="amici">{{Cite web |title=Brief of the American Psychological Association, The California Psychological Association, the American Psychiatric Association, and the American Association for Marriage and Family Therapy as amici curiae in support of plaintiff-appellees&nbsp;– Appeal from United States District Court for the Northern District of California Civil Case No. 09-CV-2292 VRW (Honorable Vaughn R. Walker) |url=http://www.ca9.uscourts.gov/datastore/general/2010/10/27/amicus29.pdf |url-status=live |archive-url=https://web.archive.org/web/20150413160709/http://cdn.ca9.uscourts.gov/datastore/general/2010/10/27/amicus29.pdf |archive-date=13 April 2015 |access-date=5 November 2010}}</ref><ref name="cpa2006">{{Cite web |year=2006 |title=Marriage of Same-Sex Couples – 2006 Position Statement Canadian Psychological Association |url=http://www.cpa.ca/cpasite/userfiles/Documents/Marriage%20of%20Same-Sex%20Couples%20Position%20Statement%20-%20October%202006%20(1).pdf |archive-url=https://web.archive.org/web/20090419195945/http://www.cpa.ca/cpasite/userfiles/Documents/Marriage%20of%20Same-Sex%20Couples%20Position%20Statement%20-%20October%202006%20%281%29.pdf |archive-date=19 April 2009}}</ref><ref>{{Cite journal |display-authors=etal |vauthors=Pawelski JG, Perrin EC, Foy JM |date=July 2006 |title=The effects of marriage, civil union, and domestic partnership laws on the health and well-being of children |journal=[[Pediatrics (journal)|Pediatrics]] |volume=118 |issue=1 |pages=349–64 |doi=10.1542/peds.2006-1279 |pmid=16818585 |s2cid=219194821 |doi-access=}}</ref><ref>{{Cite web |last=Lamb |first=Michael |title=Expert Affidavit for U.S. District Court (D. Mass. 2009) |url=http://www.glad.org/uploads/docs/cases/pedersen-v-opm/2011-09-14-pedersen-lamb-rebuttal-afffidavit.pdf |url-status=live |archive-url=https://web.archive.org/web/20150924022457/http://www.glad.org/uploads/docs/cases/pedersen-v-opm/2011-09-14-pedersen-lamb-rebuttal-afffidavit.pdf |archive-date=24 September 2015 |access-date=24 July 2012 |publisher=Gay & Lesbian Advocates & Defenders}}</ref><ref name="AAP-Discovery">{{Cite web |date=22 March 2013 |title=Pediatricians: Gay Marriage Good for Kids' Health |url=http://news.discovery.com/human/health/pediatricians-gay-marriage-is-good-for-kids-health-130322.htm |url-status=live |archive-url=https://web.archive.org/web/20141112053402/http://news.discovery.com/human/health/pediatricians-gay-marriage-is-good-for-kids-health-130322.htm |archive-date=12 November 2014 |access-date=11 April 2013 |publisher=news.discovery.com}}</ref>

Scientific research has been generally consistent in showing that lesbian and gay parents are as fit and capable as heterosexual parents, and their children are as psychologically healthy and well-adjusted as children reared by heterosexual parents.<ref name=cpa2006/><ref name="AAP-Discovery" /><ref name="apsp">{{Cite web |title=Elizabeth Short, Damien W. Riggs, Amaryll Perlesz, Rhonda Brown, Graeme Kane: Lesbian, Gay, Bisexual and Transgender (LGBT) Parented Families – A Literature Review prepared for The Australian Psychological Society |url=http://www.psychology.org.au/Assets/Files/LGBT-Families-Lit-Review.pdf |url-status=dead |archive-url=https://web.archive.org/web/20110304014530/http://www.psychology.org.au/Assets/Files/LGBT-Families-Lit-Review.pdf |archive-date=4 March 2011 |access-date=5 November 2010}}</ref><ref name="amici2010">{{Cite web |title=Brief of the American Psychological Association, The California Psychological Association, The American Psychiatric Association, and The American Association of Marriage and Family Therapy as Amici Curiae in Support of Plaintiff-Appellees |url=http://www.ca9.uscourts.gov/datastore/general/2010/10/27/amicus29.pdf |url-status=live |archive-url=https://web.archive.org/web/20150413160709/http://cdn.ca9.uscourts.gov/datastore/general/2010/10/27/amicus29.pdf |archive-date=13 April 2015 |access-date=28 September 2012 |publisher=[[United States Court of Appeals for the Ninth Circuit]]}}</ref> According to scientific literature reviews, there is no evidence to the contrary.<ref name="aap2006">{{Cite journal |last1=Pawelski |first1=J.G. |last2=Perrin |first2=E.C. |last3=Foy |first3=J.M. |last4=Allen |first4=C.E. |last5=Crawford |first5=J.E. |last6=Del Monte |first6=M. |last7=Kaufman |first7=M. |last8=Klein |first8=J.D. |last9=Smith |first9=K. |last10=Springer |first10=S. |last11=Tanner |first11=J.L. |last12=Vickers |first12=D.L. |year=2006 |title=The Effects of Marriage, Civil Union, and Domestic Partnership Laws on the Health and Well-being of Children |journal=Pediatrics |volume=118 |issue=1 |pages=349–64 |doi=10.1542/peds.2006-1279 |pmid=16818585 |s2cid=219194821 |doi-access=}}</ref><ref name="herek">{{Cite journal |last=Herek, GM |date=September 2006 |title=Legal recognition of same-sex relationships in the United States: a social science perspective |url=http://psychology.ucdavis.edu/rainbow/html/AP_06_pre.PDF |url-status=dead |journal=The American Psychologist |volume=61 |issue=6 |pages=607–21 |doi=10.1037/0003-066X.61.6.607 |pmid=16953748 |archive-url=https://web.archive.org/web/20100610164736/http://psychology.ucdavis.edu/rainbow/html/AP_06_pre.PDF |archive-date=10 June 2010}}</ref><ref name="How Does the Gender of Parents Matter?">{{Cite journal |last1=Biblarz, Timothy J. |last2=Stacey, Judith |date=February 2010 |title=How Does the Gender of Parents Matter? |url=http://www.famigliearcobaleno.org/public/documenti/file/How-Does-the-Gender-of-Parents-Matter.pdf |url-status=dead |journal=Journal of Marriage and Family |volume=72 |issue=1 |pages=3–22 |citeseerx=10.1.1.593.4963 |doi=10.1111/j.1741-3737.2009.00678.x |archive-url=https://web.archive.org/web/20130512111336/http://www.famigliearcobaleno.org/public/documenti/file/How-Does-the-Gender-of-Parents-Matter.pdf |archive-date=12 May 2013}}</ref><ref name="cpa2005">{{Cite web |title=Brief presented to the Legislative House of Commons Committee on Bill C38 by the Canadian Psychological Association – 2 June 2005. |url=http://www.cpa.ca/cpasite/UserFiles/Documents/advocacy/brief.pdf |url-status=dead |archive-url=https://web.archive.org/web/20121013225547/http://www.cpa.ca/cpasite/userfiles/Documents/advocacy/brief.pdf |archive-date=13 October 2012 |access-date=7 August 2018}}</ref>{{update needed|date=December 2023}}

Compared to heterosexual couples, same-sex couples have a greater need for [[adoption]] or [[assisted reproductive technology]] to become parents. Lesbian couples often use [[artificial insemination]] to achieve pregnancy, and [[reciprocal in vitro fertilization]] (where one woman provides the egg and the other gestates the child) is becoming more popular in the 2020s, although many couples cannot afford it. [[Surrogacy]] is an option for wealthier gay male couples, but the cost is prohibitive. Other same-sex couples adopt children or raise the children from earlier opposite-sex relationships.<ref>{{cite journal |last1=Goldberg |first1=Abbie E. |title=LGBTQ-parent families: Diversity, intersectionality, and social context |journal=Current Opinion in Psychology |date=February 2023 |volume=49 |pages=101517 |doi=10.1016/j.copsyc.2022.101517|pmid=36502588 |s2cid=253665001 |url=https://commons.clarku.edu/faculty_psychology/4 }}</ref><ref>{{cite journal |last1=Leal |first1=Daniela |last2=Gato |first2=Jorge |last3=Coimbra |first3=Susana |last4=Freitas |first4=Daniela |last5=Tasker |first5=Fiona |title=Social Support in the Transition to Parenthood Among Lesbian, Gay, and Bisexual Persons: A Systematic Review |journal=Sexuality Research and Social Policy |date=December 2021 |volume=18 |issue=4 |pages=1165–1179 |doi=10.1007/s13178-020-00517-y|hdl=10216/132451 |hdl-access=free }}</ref>

====Adoption====
{{main|LGBT adoption}}
[[File:World same-sex adoption laws.svg|center|thumb|upright=3|Legal status of adoption by same-sex couples around the world: {{legend|#800080|Joint adoption allowed}}
{{legend|#ba75ff|Second-parent (stepchild) adoption allowed}}
{{legend|#CCCCCC|No laws allowing adoption by same-sex couples and no same-sex marriage}}
{{legend|#E4D69D|Same-sex marriage but adoption by married same-sex couples not allowed}}
]]
All states that allow same-sex marriage also allow the joint [[adoption]] of children by those couples with the exceptions of Nepal, Ecuador and a third of states in Mexico, though such restrictions have been ruled unconstitutional in Mexico. In addition, Bolivia, Croatia, Israel and Liechtenstein, which do not recognize same-sex marriage nonetheless permit joint adoption by unmarried same-sex couples. Some additional states that do not recognize same-sex marriage allow stepchild adoption by couples in civil unions include Italy (on a case-by-case basis) and San Marino.{{cn|date=December 2023}}