The Church’s teachings and position on this moral issue are unequivocal. Marriage between a man and a woman is ordained of God, and the formation of families is central to the Creator’s plan for His children. Children are entitled to be born within this bond of marriage.
We ask that you do all you can to … assure that marriage … is legally defined as being between a man and a woman. Our best efforts are required to preserve the sacred institution of marriage.
The Church does not object to rights (already established in California) regarding hospitalization and medical care, fair housing and employment rights, or probate rights, so long as these do not infringe on the integrity of the family or the constitutional rights of churches and their adherents to administer and practice their religion free from government interference.
The Church has a single, undeviating standard of sexual morality: intimate relations are proper only between a husband and a wife united in the bonds of matrimony.
A husband and a wife do not receive these benefits to elevate them above any other two people who may share a residence or social tie, but rather in order to preserve, protect, and defend the all-important institutions of marriage and family.
Co-habitation under any guise or title is not a sufficient reason for defining new forms of marriage.
High rates of divorce and out-of-wedlock births have resulted in an exceptionally large number of single parents in American society. Many of these single parents have raised exemplary children; nevertheless, extensive studies have shown that in general a husband and wife united in a loving, committed marriage provide the optimal environment for children to be protected, nurtured, and raised. 
David Popenoe has said:
The burden of social science evidence supports the idea that gender differentiated parenting is important for human development and that the contribution of fathers to childrearing is unique and irreplaceable. 
Popenoe explained that:
. . . The complementarity of male and female parenting styles is striking and of enormous importance to a child’s overall development. It is sometimes said that fathers express more concern for the child’s longer-term development, while mothers focus on the child’s immediate well-being (which, of course, in its own way has everything to do with a child’s long-term well-being). What is clear is that children have dual needs that must be met: one for independence and the other for relatedness, one for challenge and the other for support. 
In recent years in the United States and other countries, a movement has emerged to promote same-sex marriage as an inherent or constitutional right. This is not a small step, but a radical change: instead of society tolerating or accepting private, consensual sexual behavior between adults, advocates of same-sex marriage seek its official endorsement and recognition
In sum, there is very strong agreement across America on what marriage is.
As Elder Dallin H. Oaks has explained,
Tolerance obviously requires a non-contentious manner of relating toward one another’s differences. But tolerance does not require abandoning one’s standards or one’s opinions on political or public policy choices. Tolerance is a way of reacting to diversity, not a command to insulate it from examination. 
Legalizing same-sex marriage will affect a wide spectrum of government activities and policies. Once a state government declares that same-sex unions are a civil right, those governments almost certainly will enforce a wide variety of other policies intended to ensure that there is no discrimination against same-sex couples. This may well place “church and state on a collision course.” 
Aside from the very serious consequence of undermining and diluting the sacred nature of marriage between a man and a woman, there are many practical implications in the sphere of public policy that will be of deep concern to parents and society as a whole. These are critical to understanding the seriousness of the overall issue of same-sex marriage.
When a man and a woman marry with the intention of forming a new family, their success in that endeavor depends on their willingness to renounce the single-minded pursuit of self-fulfillment and to sacrifice their time and means to the nurturing and rearing of their children. Marriage is fundamentally an unselfish act: legally protected because only a male and female together can create new life, and because the rearing of children requires a life-long commitment, which marriage is intended to provide. Societal recognition of same-sex marriage cannot be justified simply on the grounds that it provides self-fulfillment to its partners, for it is not the purpose of government to provide legal protection to every possible way in which individuals may pursue fulfillment. By definition, all same-sex unions are infertile, and two individuals of the same gender, whatever their affections, can never form a marriage devoted to raising their own mutual offspring.
Strong, stable families, headed by a father and mother, are the anchor of civilized society.
The Church of Jesus Christ of Latter-day Saints has chosen to become involved, along with many other churches, organizations, and individuals, in defending the sanctity of marriage between a man and a woman because it is a compelling moral issue of profound importance to our religion and to the future of our society.
 David Blankenhorn, Fatherless America: Confronting Our Most Urgent Social Problem (New York: Basic Books, 1995); Barbara Schneider, Allison Atteberry, and Ann Owens, Family Matters: Family Structure and Child Outcomes (Birmingham AL: Alabama Policy Institute: June 2005); David Popenoe, Life Without Father (New York: Martin Kessler Books, 1996); David Popenoe and Barbara Defoe Whitehead, The State of Our Unions 2007: The Social Health of Marriage in America (Piscataway, NJ (Rutgers University): The National Marriage Project, July 2007 ) pp. 21-25; and Maggie Gallagher and Joshua K. Baker, “Do Moms and Dads Matter? Evidence from the Social Sciences on Family Structure and the Best Interests of the Child,” Margins Law Journal 4:161 (2004).
 David Popenoe, Life Without Father (New York: The Free Press, 1996) p. 146.
 Ibid., p. 145. See also Spencer W. Kimball, “The Role of Righteous Women,” Ensign, November 1979, pp. 102-104.
 Elder Dallin H. Oaks, “Weightier Matters,” BYU Devotional speech, 9 February 1999.
 Maggie Gallagher, “Banned in Boston: The Coming Conflict Between Same-Sex Marriage and Religious Liberty,” The Weekly Standard, 15 May 2006.
My Thoughts as I read through these:
If we see homosexuality as a sin you can't forget the mantra, "Hate the sin, love the sinner."
Can’t regulate our religion, but we can defend a moral society. This subject is difficult b/c it doesn’t directly infringe upon our rights, but can through potential societal harm of 1) promoting raising children w/o male and female parents rather than making the best of situations when it arises, 2) lower moral compass for society.
It isn’t healthy or democratic for one camp or another to try and ridicule the other into silence.
On the other hand, I feel for those who have SSA, I believe that for some SSA is from a genetic predisposition, not a self induced mental condition. One of the saddest things in my life was seeing the pain that a SSA person went through trying to deal with their SSA and religious society’s general naïve view of it.
Would it have been better for the church to sit quietly on the side and avoid being the "poster child" for anti prop 8 issues? At the same time, when were we a church that didn’t stand up for morality?
The church leadership obviously feels that w/o marriage being defined as between a man and a woman, society will continue to erode at a faster pace and potentially the church will lose some of its religious freedoms in the name of equality. The Church canon, including the BOM state that we should not impose our beliefs on others. At the same time we should help strengthen the moral backbone of society as a responsibility to our God and future generations.
This post isn't meant to be an end all for information on the church's stance or how you should feel about the subject. It is mainly to explore some of the statements given and some of my thoughts on the subject. To me the question is not whether or not the Church should change its position on SSA. The question should be, where is the line between imposing our religion on others and helping keep the moral fabric of society strong. Allowing SSMs to have many equal rights, but not all seems to be what the church is stating. Where that line is though can be difficult to draw...
Further links to church publication on this topic http://newsroom.lds.org/ldsnewsroom/eng/commentary/same-sex-marriage-and-proposition-8