1) Halachic ways to give a daughter a share of the inheritance, and their drawbacks
There are, however, a number of ways that a person can use to ensure that his daughters also benefit from his inheritance.
The first and most obvious is to give a present to his daughter in his lifetime. As long as a person is alive he is certainly entitled to do with his possessions as he sees fit, including giving it away to whomever he wishes. However, most people do not want to give away their possessions as long as they live, because they wish to use them themselves, and therefore require a method whereby they can give away their possessions after their death.
Another option available is to give a Matnas Sh’chiv Mera. Chazal were concerned that a person on his deathbed who was unable to divide up his possessions in the manner he wishes might become so upset that his condition may deteriorate to the point of hastening his demise. In order to avoid this, they instituted that a person on his deathbed has the power to give away his possessions merely by oral instruction, without actually physically giving things over. This device is known as a Matnas Sh’chiv Mera. This is also not practical for the general purpose of bequeathing to a daughter because people do not know when they will die, and when the time does come, they may have little or no advance warning. Even if they do know shortly beforehand, they may be too unwell at that point to arrange anything.
Yet another option is to give away, in one’s lifetime, the property with the explicit proviso that the original owner retains all rights of the usage of the property until his death. In the classic example, a person can give over a tree to someone else and yet retain the rights to all the fruits that the tree continues to produce in his lifetime (“Guf mehayom upeiros le’achar missoh”). Similarly with anything else, one can give over the actual object whilst at the same time retaining the rights of all usage of the object (the “fruit” that the object produces, so to speak) as long as one lives. In such cases, when the person dies, the property does not pass automatically to his inheritors, since someone else already owns the actual property, and it is this party who now receives automatically the complete rights to the property.
There are two drawbacks to this method. Firstly, once one has given away even just the body of the property, one cannot retract on the transaction. Just as with any other transaction that, once effected, cannot be annulled, so too, even if one retains the right to use the property, nonetheless the property itself now belongs to someone else and thus the original owner has no way to give it to someone else should he desire. As such, if someone gives away the body of his property in his lifetime, even if he retains the right to use it for the duration of his lifetime, he will be unable to change his mind at a later date.
Uniquely, though, in the case of someone who gives away part of his property to his daughter in his lifetime (with the proviso that he may use the property himself during his lifetime), he may be able to change his mind and give it away to someone else in his lifetime. In a case where a man used this method to give his daughter a share in his inheritance equivalent to half of that of each of his sons, the Remo”h rules that he may still sell or give away his property in his lifetime. This ruling is based on that of the Mordechai, who states that since the man explicitly stated that his daughter should take a share in the inheritance equivalent to half of that of his sons, he clearly did not wish to empower her more than had she been a legal inheritor. Just as his sons only inherit that which he has not disposed of in his lifetime, so too he intends that his daughter should inherit a share in what will be left after his death. Although the share in the property belongs to her immediately (since the man said that he is giving over the body of the property immediately with rights of usage to be received by his daughter after his death), by saying that he wishes her to receive a portion in a similar manner to his sons, it is as if the man expressly specified that he retains the right to give it away to others during his lifetime.
There is another problem with this method, though. A person cannot give away something that he does not yet own. Therefore, if someone would wish to give his daughter a share in his inheritance by giving her the body of the property whilst retaining the rights of use for the rest of his life, it would only work for possessions that he owned at the time. Any possessions that would come into his ownership after this transaction would not be included in the transaction. As such, this method will not help those who wish to make arrangements well in advance of their demise, whilst at the same time including in the arrangements all possessions that they will own at the time of their passing.