My law practice is concentrated in estate planning and business consulting. Most of my estate planning clients are lesbians and gay men. Most are in a committed relationship. An increasing number are raising children.
First, let's get some things, ahem, straight. You don't need children to be a family. Most lesbian and gay couples are not raising children. Most gay and lesbian couples live in non-recognition states. Those are the ones that do not recognize lesbian and gay relationships. And, most lesbian and gay couples have not done any estate planning. That is a mistake.
I thought a primer on estate planning might be helpful:

The basic estate plan documents are: Will, Living Will, Health Care Power of Attorney, General Durable Power of Attorney, HIPAA Authorization and a Designation of Agent.
A more advanced estate plan can involve trusts. There are myriad types of trusts: living trusts, testamentary trusts, charitable trusts, charitable remainder trusts, revocable and irrevocable trusts, insurance trusts, etc..
Most people, at least most of the folks I talk to, want to avoid probate. Probate happens after you die. You can have probate assets and non-probate assets. If something has a title to it, like a car, it may go through probate. Some states allow you to transfer the title to a named beneficiary when you die. That makes the car a non-probate asset.
Insurance policies allow you to name a beneficiary. If you do, the insurance company cuts a check to your named beneficiary and mails it. This is a non-probate asset. Some people name their estate as the beneficiary of their life insurance. Doing so makes the insurance proceeds a probate asset. If you have a Will, your designated beneficiaries will get it. But, probate can be expensive. It's cheaper and faster to name a beneficiary on the policy.
Dying without a Will
If you die without a Will, you die "intestate". Then state law determines who gets your stuff. Let's assume you don't have a house. Your assets are your computer, a car, furniture, household goods and your clothes. Without a Will, all of your stuff will be given to your relatives in the order specified by a state law. Usually, the order of succession is: Spouse, Children, Parents, Siblings, Grandparents, Aunts/Uncles, Cousins and on down the line.
When you die with a Will, you die "testate". The Will allows you to name the person or persons who will inherit your stuff.
You do not need to be rich to have a Will. You just need to have stuff...and we all have lots of stuff.
Lesbian and Gay Couples
35 states do not recognize lesbian and gay relationships. Only 6 states (Massachusetts, Iowa, Vermont, New Hampshire, Connecticut and New York) and the District of Columbia, recognize same-sex marriages.
The state legislatures in Maryland and Washington passed marriage equality laws. However, those laws are being contested and will be on the ballot in November 2012--another reason to vote.
Hawii, Colorado, Maine and Wisconsin provide limited legal rights for lesbian and gay couples.
For lesbian and gay couples who want to make sure their partner inherits everything, a Will is essential. It is the best way to protect your partner. Without one, the surviving partner may get nothing, especially if you live in a non-recognition state.
If you live in a non-recognition state--and there are 35 of them--and die without a Will, your surviving partner will not inherit anything from you.
Marriage
The Defense of Marriage Act (DOMA) allows every state to refuse to recognize a marriage between two men or two women.
Just because you were married in one of the 6 states mentioned or the District of Columbia does not mean your marriage will be recognized everywhere. In fact, most states won't recognize the marriage.
And, don't bother yelling about how unfair it is. The law controls, not common sense or fairness.
DOMA is being challenged on many fronts. Right now, there are lawyers asking the United States Supreme Court to hear several cases where federal courts have ruled that DOMA is unconstitutional.
Children
Any gay or lesbian individual or couple who is raising children needs a Will. It is just plain dumb to be raising kids and not have a Will.
A Will allows you to name the person who will be responsible for your kids if you die. If you don't name a guardian or don't have a Will, the probate court will decide where the kids go. Your children may end up with a relative you hate. And, remember, you are dead so there is nothing you can do about it.
Now is the time to protect your children.
If your partner can adopt the children you are raising, start the process. Do not delay. That court order is enforceable in every state.
DIY Estate Planning
There are websites where you can write your own Will at a very low cost. In some situations, this may work just fine. However, for lesbians and gay men, in or out of a relationship, doing it yourself may not be in your best interests.
And, for lesbian and gay couples who are raising children, you need more than what you'll get from those sites. For the most part, they are designed for heterosexual couples and parents. In most states, the families of lesbians and gay men are not afforded the same protections as heterosexual families.
You need a lawyer that is experienced with LGBT legal issues. That does not mean a straight lawyer cannot do the job. It does mean you should not do it yourself. Remember, you won't know if it's right until after you're dead and then it's too late.
A Will allows you the opportunity to pass on your assets to whomever you choose. It's the foundation for every estate plan.
Every state has its own laws concerning inheritance, children, Wills, trusts and the like.
Do yourself a favor and work with an experienced lawyer. It will allow you to make sure your final wishes are carried out.